Single- versus bi-socket anterior cruciate ligament reconstruction using autogenous multiple-stranded hamstring tendons with endoButton femoral fixation: A prospective study

Hamstring Graft Prepared With Suture Tape Is Effective in Anterior Cruciate Ligament Reconstruction: A Biomechanical Analysis

Purpose

To investigate the graft diameters and mechanical properties of hamstring tendons sutured using different materials and techniques.

Methods

This study used 30 fresh, frozen human cadaveric semitendinosus tendons; the free ends of 10 specimens each were sutured by 2 No. 3 braided polyester sutures with the Krackow technique (BP group), SutureTape with the Krackow technique (ST group), or SutureTape Loop with the locking SpeedWhip technique (SL group). First, the changes in graft diameter from before suturing to after suturing were investigated. Each graft was pre-tensioned to 100 N for 3 cycles and then cyclically loaded to 200 N for 200 cycles. Elongation after cyclic loading and displacement in the 200th cycle were calculated. Finally, each specimen was loaded to failure. The ultimate failure load and stiffness were analyzed. These mechanical properties were statistically analyzed using 1-way analysis of variance. The level of statistical significance was set at P < .05.

Results

In the BP group, the changes in graft diameter were significantly larger than those in the ST and SL groups (P = .001). The elongation values after 200 cycles in the BP and ST groups were 3.1 ± 2.0 mm and 5.9 ± 3.4 mm, respectively. In the SL group, elongation (7.7 ± 3.6 mm) was significantly larger compared with that in the BP group (P = .037). In contrast, displacement in the 200th cycle was significantly smaller in the ST and SL groups compared with the BP group (P = .017). No statistically significant difference was evident for the ultimate failure loads among the 3 groups (P = .543).

Conclusions

The results of this study suggest that SutureTape may be an appropriate option for preparing the hamstring graft in anatomic anterior cruciate ligament (ACL) reconstruction.

Clinical Relevance

This biomechanical study shows the effectiveness of SutureTape in ACL graft preparation. Clinically, SutureTape may be of benefit in single- or double-bundle ACL reconstruction.

Does a combined screw and dowel construct improve tibial fixation during anterior cruciate ligament reconstruction?

PURPOSE

The aims of the present study were to compare the biomechanical properties of tibial fixation in hamstring-graft ACL reconstruction using interference screw and a novel combination interference screw and dowel construct.

MATERIAL AND METHODS

We compared the fixation of 30 (2- and 4-stranded gracilis and semitendinosis tendons) in 15 fresh-frozen porcine tibiae with a biocomposite resorbable interference screw (Group 1) and a screw and dowel construct (Group 2). Each graft was subjected to load-to-failure testing (50 mm/min) to determine maximum load, displacement at failure and pullout strength.

RESULTS

There were no significant differences between the biomechanical properties of the constructs. Multivariate analysis demonstrated that combination constructs (β = 140.20, p = 0.043), screw diameter (β = 185, p = 0.006) and 4-strand grafts (β = 51, p = 0.050) were associated with a significant increase in load at failure. Larger screw diameter was associated with increased construct stiffness (β = 20.15, p = 0.020).

CONCLUSION

The screw and dowel construct led to significantly increased fixation properties compared to interference screws alone in a porcine model. Increased screw diameter and utilization of 4-strand ACL grafts also led to improvement in load-to-failure of the construct. However, this is an in vitro study and additional investigations are needed to determine whether the results are reproducible in vivo.

LEVEL OF EVIDENCE

Level V; Biomechanical study.

A Cross-sectional Examination of Quadriceps Strength, Biomechanical Function, and Functional Performance From 9 to 24 Months After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Patients who undergo anterior cruciate ligament reconstruction (ACLR) have deficiencies in strength, functional performance, and biomechanical function at return to activity. Patients who have abnormal strength and function after ACLR may be at a greater risk for secondary injury and posttraumatic osteoarthritis.

PURPOSE

To examine quadriceps strength, functional performance, and knee biomechanics in patients who are 9, 12, 18, and 24 months after ACLR.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

We recruited 82 participants (45 female) who underwent ACLR and were cleared to return to activity . Participants were assigned to 1 of 4 groups based on their time from ACLR: 9 months (285.26 ± 8.16 days), 12 months (373.59 ± 8.81 days), 18 months (557.50 ± 11.96 days), and 24 months postoperative (741.05 ± 11.86 days). Quadriceps strength was measured concentrically at 60 deg/s. Functional performance was assessed by measuring maximal hop distances or heights during dynamic hopping/jumping tests (single-leg hop, triple hop, crossover hop, and single-leg vertical hop). Biomechanical function was evaluated during the dynamic hop tests by using peak sagittal plane knee flexion angles recorded during landings. Strength, performance, and biomechanics data were collected for both limbs and reported as symmetry scores ([injured/uninjured] × 100). Self-perceived function was measured using the International Knee Documentation Committee subjective knee form.

RESULTS

Quadriceps strength in the 9-month (77.61 ± 16.73) and 12-month (77.80 ± 13.99) groups was significantly lower (P < .01) compared with the 24-month group (92.40 ± 15.55). Self-perceived function for the 9-month group (79.33 ± 10.40) was significantly lower (P < .01) when compared with 12-month (87.58 ± 10.29), 18-month (89.81 ± 8.36), and 24-month (91.59 ± 5.70) groups. Single-leg hop distance symmetry was significantly lower (P < .01) for the 9-month group (90.01 ± 9.46) when compared with the 18-month (96.24 ± 6.47) and 24-month (96.30 ± 6.46) groups; triple hop symmetry was significantly lower (P < .05) for the 9-month group (90.26 ± 10.03) when compared with the 18-month (96.83 ± 9.60) and 24-month (95.91 ± 6.36) groups; and crossover hop was significantly lower (P < .05) for the 9-month group (88.35 ± 13.53) when compared with the 18-month (95.85 ± 8.63) and 24-month (97.10 ± 4.12) groups.

CONCLUSION

Quadriceps strength, self-perceived function, and functional performance improve 9 to 24 months after ACLR, indicating that recovery is ongoing after return to activity. Return-to-activity criteria after ACLR should objectively account for strength and function.

Effectiveness of Reconstruction of the Anterior Cruciate Ligament with Quadrupled Hamstrings and Bone-Patellar Tendon-Bone Autografts

Background

The 2 most frequently used autografts for anterior cruciate ligament reconstruction are the bone-patellar tendon-bone and the quadrupled hamstrings tendon.

Hypothesis

Hamstring tendon graft is superior to patellar tendon graft in restoring tibial rotation during highly demanding activities because of its superiority in strength and linear stiffness and because it is closer morphologically to the anatomy of the natural anterior cruciate ligament.

Study Design

Case control study; Level of evidence, 3.

Methods

Eleven patients with patellar tendon graft anterior cruciate ligament reconstruction, 11 patients with hamstring tendon graft anterior cruciate ligament reconstruction, and 11 controls were assessed. Kinematic data were collected (50 Hz) with a 6-camera optoelectronic system while the subjects descended stairs and, immediately after, pivoted on their landing leg. The dependent variable examined was the tibial internal-external rotation during pivoting. All patients in both groups were also assessed clinically and with the use of a KT-1000 arthrometer to evaluate anterior tibial translation.

Results

The results demonstrated that reconstructions with either graft successfully restored anterior tibial translation. However, both anterior cruciate ligament reconstruction groups had significantly increased tibial rotation when compared with the controls, whereas no differences were found between the 2 reconstructed groups.

Conclusion

The 2 most frequently used autografts for anterior cruciate ligament reconstruction cannot restore tibial rotation to normal levels.

Clinical Relevance

New surgical techniques are needed that can better approximate the actual anatomy and function of the anterior cruciate ligament.

Endoscopic Harvest of Autogenous Gracilis and Semitendinosus Tendons

The hamstring autograft is one of the most popular grafts for anterior cruciate ligament (ACL) reconstruction. Although many techniques for arthroscopic ACL reconstruction using hamstring autografts have been invented, hamstring harvest techniques have not been focused. Hamstrings are harvested using an open technique that requires a 2- to 5-cm skin incision. In this Technical Note, we describe an endoscopic harvest technique of autogenous gracilis and semitendinosus tendon. This technique needs only a 1- to 1.5-cm skin incision and provides surgeons a sufficient view to safely harvest the hamstrings.

Beneficial and limiting factors for return to work following anterior cruciate ligament reconstruction: a retrospective cohort study

PURPOSE

Evidence-based advice for return to work (RTW) after anterior cruciate ligament (ACL) reconstruction is not available. Therefore, the objectives of this study were to determine when patients achieve full RTW, and to explore the beneficial and limiting factors for fully RTW after ACL reconstruction.

METHODS

A retrospective cohort study was performed after ACL reconstruction among 185 patients in one hospital. Data from patient files and a questionnaire were used to explore whether patient-, injury-, surgery-, sports-, work- and rehabilitation-related factors are beneficial or limiting for fully RTW after ACL reconstruction, using a backward stepwise logistic regression analysis.

RESULTS

Of the 125 (68%) patients that returned the questionnaire, 36 were not part of the working population. Of the remaining 89 patients, 82 patients (92%) had returned fully to work at follow-up. The median time to fully RTW was 78 days. In the final regression model, which explained 29% of the variance, a significant OR of 5.4 (90% CI 2.2-13.1) for RTW > 78 days was observed for patients performing heavy knee-demanding work compared to patients performing light knee-demanding work. In addition, a significant and positive OR (1.6, 90% CI 1.2-1.9) for the number of weeks walking with the aid of crutches for RTW > 78 days was observed in the final model.

CONCLUSION

After ACL reconstruction, 92% of the patients fully return to work at a median time of 78 days. The significant predictors for fully RTW > 78 days are performing heavy knee-demanding work and a longer period of walking aided with crutches after ACL reconstruction.

Prospective Randomized Study of Objective and Subjective Clinical Results Between Double-Bundle and Single-Bundle Anterior Cruciate Ligament Reconstruction

BACKGROUND

There is controversy as to whether double-bundle anterior cruciate ligament (ACL) reconstruction with hamstring tendon graft (DB-HT) or single-bundle ACL reconstruction with patellar tendon graft (SB-PT) obtains the best clinical outcomes.

PURPOSE

To compare the short-term clinical outcomes of DB-HT with those of rectangular-tunnel SB-PT (RTSB-PT) at 2-year follow-up and to identify the factors that affect subjective knee functional score.

STUDY DESIGN

Randomized controlled trial. Level of evidence, 1.

METHODS

Sixty-three male patients (mean age, 26.1 years) and 87 female patients (mean age, 25.8 years) were included in this study and were randomly distributed to either the DB-HT (n = 76) or RTSB-PT (n = 74) group. Clinical outcomes (knee flexion range of motion [ROM], heel-height difference, side-to-side difference in anterior laxity, rotational laxity, and Tegner activity score) were compared between the DB-HT and RTSB-PT groups, and examination of factors affecting subjective outcomes (Knee Injury and Osteoarthritis and Outcome Score [KOOS] results) was performed by multiple linear regression analysis.

RESULTS

Fourteen patients (9 DB-HT, 5 RTSB-PT) had secondary ACL injury within 2 years after primary ACL reconstruction and were excluded from analysis. In the examination of 136 patients at the 24-month follow-up, there was no significant difference between the 2 groups in clinical or subjective outcomes. The normalized knee extensor strength of the RTSB-PT group showed negative surgical technique effect in the early postoperative phase (P = .005), but there was no significant difference between the 2 groups at the 24-month follow-up (P = .114). There was no significant difference in change of normalized knee flexor strength between the 2 groups (P = .493). Age, sex, body mass index (BMI), and presence of meniscus injury were the factors that affected KOOS subscale scores.

CONCLUSION

In this prospective randomized controlled study, there was no significant difference in the incidence of secondary ACL injury and no difference in objective or subjective outcomes between the DB-HT and RTSB-PT reconstruction at 24-month follow-up. Age, sex, presence of meniscus injury, and BMI affected subjective KOOS subscale scores, while surgical technique did not.

Single- vs. double-bundle anterior cruciate ligament reconstruction: a new aspect of knee assessment during activities involving dynamic knee rotation

Few studies have compared single-bundle (SB) and double-bundle (DB) anterior cruciate ligament reconstruction (ACLR) in the knee joint during activities involving change-of-direction maneuvers and knee rotation. This study examined whether the type of ACLR contributes to postphysiotherapy outcomes, with an emphasis on knee function assessment during activities involving dynamic knee rotation. Fifteen male patients after SB ACLR and 15 male patients after DB ACLR took part in the same physiotherapy program. Twenty-four weeks after ACLR, both groups underwent anterior laxity measurement, pivot shift tests, range of movement and joint circumference measurements, subjective assessment of pain and stability levels in the knee joint, peak torque measurement of the muscles rotating the tibia toward the femur, and a run test with maximal speed and change-of-direction maneuvers. Comparative analysis did not show any differences between the results of anterior tibial translation, pivot shift test, range of movement and joint circumference, and subjective assessment of pain and knee joint stability levels. No differences were noted between the groups in peak torque values obtained from the muscles responsible for internal and external tibial rotation or results of the run test. The data obtained from this study can be used by research teams to monitor and compare the effectiveness of various study protocols involving surgical and physiotherapy treatment. The data are especially useful when combined with the clinical assessment of patients who would like to return to sport.

Arthroscopic anatomic double bundle anterior cruciate ligament reconstruction: Our experience with follow-up of 4 years

BACKGROUND

Double bundle (DB) anterior cruciate ligament (ACL) reconstruction has been proposed to recreate the natural anatomy of ACL. Reconstruction of the anatomy of both the bundles of ACL has been thought to be able to restore the rotational stability of the knee joint. Nevertheless, it remains unclear whether DB reconstruction has better functional outcome than single bundle (SB) ACL reconstruction.

PURPOSE

To evaluate the clinical outcomes, patient satisfaction and manual laxity tests of knee in patients treated with DB ACL reconstruction in Indian population.

METHODS

We prospectively followed 25 patients with an isolated ACL injury operated for DB ACL reconstruction after applying the inclusion and exclusion criteria. Patients were evaluated pre-operatively and in the post-operative period at regular intervals with the minimum follow up of 4 years. Clinical stability was assessed by anterior drawer test, Lachman test and pivot shift test. Functional outcome was assessed by IKDC, Lysholm and Modified Cincinnati scores.

RESULTS

At the end of 4 years, functional outcome in terms of all subjective scores was satisfactory. Graded stability results of the Lachman, Anterior drawer and pivot shift tests were almost near to that in normal knee. No complication occurred post-operatively.

CONCLUSION

Anatomical DB ACL reconstruction seems to offer satisfactory results in terms of subjective scores and stability tests to patients with ACL tear. It has been found to be associated with no obvious complications and no failures. However a larger patient pool is desired for conclusive results.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

Therapeutic, randomized controlled study, Level II.

Kinematics of Rotation in Joints of the Lower Limbs and Pelvis during Gait: Early Results-SB ACLR Approach versus DB ACLR Approach

It is difficult to find publications comparing rotation kinematics in large joints of the lower limbs and pelvis during gait in patients after single-bundle (SB) reconstruction of the anterior cruciate ligament (ACLR) with double-bundle (DB) ACLR of the knee. The aim of this study was to compare rotation kinematics in ankle, knee, and hip joints and the pelvis during gait in the 14th week after SB and DB ACLR. The subjects were males after SB (n = 10) and DB (n = 13) ACLR and a control group (n = 15). The values of kinematic parameters were recorded during internal (IR) and external (ER) rotation in the joints during gait using the BTS SMART. The SB ACLR group obtained significantly higher values of ER in the involved knee comparing to DB ACLR and controls and excessive IR in the hip comparing to controls. In the DB ACLR group, excessive ER was noted in the involved leg's foot. Comparing with the DB ACLR and control groups, SB ACLR subjects had more substantial disorders of rotation kinematics in the lower limb joints. However, in both ACLR groups, 14 weeks of postoperative physiotherapy were not enough to fully restore rotation kinematics in joints of the lower limbs during gait.

Intercondylar notch size influences cyclops formation after anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to investigate the incidence of cyclops lesions and its relationship with the cross-sectional area of the intercondylar notch.

METHODS

For this study, 55 patients (24 male and 31 female) underwent follow-up arthroscopy after bi-socket anterior cruciate ligament reconstruction with hamstring tendon grafts were included. All patients underwent magnetic resonance imaging measurements of intercondylar notch dimensions. We compared the femoral intercondylar notch sizes and bone tunnel sizes between knees with cyclops lesions (cyclops group) and those without cyclops lesions (no-cyclops group). The mean percentage of the tunnel size to the cross-sectional area of the femoral intercondylar notch was also compared between the groups. The median follow-up duration was 3.8 years.

RESULTS

Cyclops lesions were found in 15 of the 55 knees (27.3 %) on second-look arthroscopy (cyclops group). Only 6 of the 55 knees (10.9 %) had extension loss (cyclops syndrome). The cyclops group included 3 men and 12 women. The two groups showed a statistical difference in sex variation (P = 0.04). No significant differences were found in the femoral and tibial tunnel sizes between the two groups. The cross-sectional area of the femoral intercondylar notch was significantly smaller in the cyclops group (251.7 ± 63.2 mm(2)) than in the no-cyclops group (335.6 ± 77.6 mm(2)) (P < 0.001). The percentage of the total femoral tunnel size to the cross-sectional area of the femoral intercondylar notch was significantly higher in the cyclops group (18.6 ± 5.3 %) than in the no-cyclops group (13.2 ± 3.6 %) (P = 0.02).

CONCLUSIONS

A smaller intercondylar notch size may be a potential risk factor for cyclops lesion formation.

LEVEL OF EVIDENCE

Case-control study, Level IV.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Case series, Level IV.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

MRI analysis of single-, double-, and triple-bundle anterior cruciate ligament grafts

PURPOSE

The purpose of the study was to evaluate the entire course of ACL grafts on coronal oblique MR images, focusing on differences in graft morphology and graft-to-tunnel healing among single-bundle (SB), double-bundle (DB), and triple-bundle (TB) reconstructions.

METHODS

Eighty-three patients underwent anatomical ACL reconstruction using the semitendinosus tendon. SB reconstruction was performed on 20 patients, DB on 29 patients, and TB on 34 patients. The anteromedial-bundle (AMB) and posterolateral-bundle (PLB) images were extracted from coronal oblique images of grafts at 6 months to visualize their entire course. Signal intensity of grafts was measured independently in three regions: (1) intra-femoral tunnel region, (2) intra-articular region, and (3) intra-tibial tunnel region, followed by calculation of the signal-to-noise quotient (SNQ). To evaluate graft-to-tunnel healing, T2-weighted images were examined for the presence of a high signal-intensity lesion between the graft and bone tunnel around the tunnel aperture.

RESULTS

AMB images showed that SB graft was thick throughout the entire course, while DB graft was thinner than SB graft. TB graft showed a fan shape approaching the tibial tunnels. The SNQ in the femoral tunnel of SB graft was significantly lower than in the DB and TB grafts. High signal-intensity lesions were frequently observed around the femoral tunnel aperture in PLB images of DB and TB grafts compared to SB grafts.

CONCLUSION

Gross morphology of TB grafts resembled that of the natural ACL. However, the graft-to-tunnel healing around the femoral tunnel seemed to be insufficient in PLB images of DB and TB compared to SB grafts.

Progression of osteoarthritis after double- and single-bundle anterior cruciate ligament reconstruction

BACKGROUND

No consensus has been reached on the advantages of double-bundle (DB) anterior cruciate ligament reconstruction (ACLR) over the single-bundle (SB) technique, particularly with respect to the prevention of osteoarthritis (OA) after ACLR.

PURPOSE

To evaluate whether DB ACLR has any advantages in the prevention of OA or provides better stability and function after ACLR compared with the SB technique.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

A total of 130 patients with an ACL injury in one knee were prospectively randomized into a DB group (n = 65) or an SB group (n = 65). For the radiologic evaluation, we determined the degree of OA based on the Kellgren-Lawrence grade before the operation and at the time of the final follow-up and determined the number of patients with progression of OA more than one grade from pre- to postoperation. We evaluated the stability results using the Lachman and pivot-shift tests and stress radiography. We also compared the functional outcomes based on the Lysholm knee score, Tegner activity score, and International Knee Documentation Committee (IKDC) subjective scale.

RESULTS

Six patients (4 in the DB group and 2 in the SB group) suffered graft failure during the follow-up and had ACL revision surgery (P = .06). A total of 112 patients were observed for a minimum of 4 years (DB group, n = 52; SB group, n = 60). Five patients (9.6%) in the DB group and 6 patients (10%) in the SB group had more advanced OA at the final follow-up (P = .75). All patients recovered full range of motion within 6 months from surgery. Stability results of the Lachman test, pivot-shift test, and the radiographic stability test failed to reveal any significant intergroup differences (P = .37, .27, and .67, respectively). In the pivot-shift result, the DB group had 4 patients with grade 2 and the SB group had 3 patients with grade 2 (P = .27). Clinical outcomes, including Lysholm knee and Tegner activity scores, were similar in the 2 groups. Statistical significance was achieved only for the IKDC subjective scale (78.2 in DB group vs 73.1 in SB group; P = .03).

CONCLUSION

The DB technique, compared with SB, was not more effective in preventing OA and did not have a more favorable failure rate. Although the DB ACLR technique produced a better IKDC subjective scale result than did the SB ACLR technique, the 2 modalities were similar in terms of clinical outcomes and stability after a minimum 4 years of follow-up.

Strategies for revision surgery after primary double-bundle anterior cruciate ligament (ACL) reconstruction

PURPOSE

The purpose of this article was to discuss pre- and intra-operative considerations as well as surgical strategies for different femoral and tibial tunnel scenarios in revision surgery following primary double-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

Based on the current literature of ACL revision surgery and surgical experience, an algorithm for revision surgery after primary double-bundle ACL reconstruction was created.

RESULTS

A guideline and flowchart were created using a case-based approached for revision surgery after primary double-bundle ACL reconstruction.

CONCLUSION

Revision surgery after primary double-bundle ACL reconstruction can be a challenging procedure that requires flexibility and a repertoire of surgical techniques. The combination of pre-operative planning with 3D-CT reconstruction, in addition to careful intra-operative assessment, and the use of this flowchart can simplify the ACL revision procedure.

LEVEL OF EVIDENCE

V.

Double-bundle reconstruction results in superior clinical outcome than single-bundle reconstruction

PURPOSE

To compare the short- and long-term clinical outcomes of the double-bundle (DB) anterior cruciate ligament (ACL) reconstruction with those of single-bundle (SB) ACL reconstruction.

METHODS

An electronic search of the database PubMed (1966-September 2011), EMBASE (1984-September 2011), and Cochrane Controlled Trials Register (CENTRAL; 3rd Quarter, 2011) was undertaken to identify relevant studies. Main clinical outcomes were knee stability measurements including KT-1000 arthrometer measurement, Pivot shift test, and Lachman test, and clinical outcome measurements including International Knee Documentation Committee (IKDC), Lysholm knee score, Tegner activity score, and complications.

RESULTS

Eighteen studies were finally included in this meta-analysis, which were all classified as high risk of bias according to the Collaboration's recommended tool. It is seen that compared to SB ACL reconstruction, DB ACL reconstruction results in a KT-1000 arthrometer outcome 0.63 and 1.00 mm closer to the normal knee in a short- and long-term follow-up, respectively. Our results also reveal that DB-treated patients have a significantly higher negative rate of the pivot shift test (p < 0.00001 and = 0.006 in a short- and long-term follow-up, respectively) and Lachman test (n.s. and p < 0.0001 in a short- and long-term follow-up, respectively) compared to SB-treated patients. As for the clinical outcome measurements, a significant difference is found between SB versus DB ACL reconstruction regarding the IKDC (p = 0.006 and < 0.0001 in a short- and long-term follow-up, respectively) and complications (p = 0.03), while there is no significant difference between the two groups regarding Lysholm knee score (n.s.) and Tegner activity score (n.s.).

CONCLUSION

Overall, double-bundle ACL reconstruction yields better clinical outcomes when compared to single-bundle ACL reconstruction.

LEVELS OF EVIDENCE

II.

Intertunnel relationships in combined anterior cruciate ligament and posterolateral corner reconstruction: an in vivo 3-dimensional anatomic study

BACKGROUND

Combined anterior cruciate ligament (ACL) and posterolateral corner (PLC) injuries are relatively common, and tunnel convergence could occur in combined ACL and PLC reconstruction.

PURPOSE

This study sought to elucidate the ranges of angles and distances of lateral collateral ligament (LCL) and popliteus tendon (PT) femoral tunnels that do not violate the intercondylar notch distally and ACL tunnels proximally during combined ACL and PLC reconstruction.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Three-dimensional anatomic knee models were developed using customized software from computed tomography images of 14 patients at 0°, 90°, and 120° of flexion. Single-bundle (SB) and double-bundle (DB) ACL tunnels using the transtibial method for anteromedial bundles and the anteromedial portal method for posterolateral bundles were created. The ranges of safe angles and distances were measured at 10° and 20° posterior, neutral (0°), and 10° and 20° anterior on the horizontal plane relative to the transepicondylar axis from the isometric LCL and PT femoral insertions. The SB ACL reconstruction using the accessory medial portal and LCL reconstruction using the anatomic footprint were also analyzed.

RESULTS

Distal and proximal angles from insertions of the LCL and PT, not violating the intercondylar notch or the ACL tunnels, increased as the LCL or PT headed from a posterior to anterior direction. Safe distances from the LCL and PT femoral insertions were approximately over 35 mm distally and 30 mm proximally. For SB ACL reconstruction using the accessory medial portal, safe angles were larger proximally than those of SB ACL reconstruction using the transtibial technique. For LCL reconstruction using the anatomic footprint, proximal angles were significantly smaller than those of the isometric LCL.

CONCLUSION

Considering the relationship between the LCL and PT tunnels and fixation strength, tunneling will be safe when the LCL and PT are positioned at an angle of approximately 20° anterior and 10° proximal to the transepicondylar axis.

CLINICAL RELEVANCE

These results will help to reduce the incidence of tunnel convergence in combined ACL and PLC reconstructions.

Effects of anterior cruciate ligament reconstruction on in vivo, dynamic knee function

The purposes of this article are to discuss key factors for assessing joint function, to present some recent findings, and to address the future directions for evaluating the function of the anterior cruciate ligament-injured/reconstructed knees. Well-designed studies, using state-of-the art tools to assess knee kinematics under in vivo, dynamic, high-loading conditions, are necessary to evaluate the relative performance of different procedures for restoring normal joint motion.

The function of the human anterior cruciate ligament and analysis of single- and double-bundle graft reconstructions

CONTEXT

There exists controversy on the ability of a single or double anterior cruciate ligament graft technique to restore anterior cruciate ligament function. This article examines the published experimental and clinical data supporting these surgical procedures in the ability to restore knee stability.

EVIDENCE ACQUISITION

An analysis of anterior cruciate ligament function and single- and double-graft reconstructions defined by selected biomechanical, robotic, kinematic, anatomical, and clinical studies.

RESULTS

The anterior cruciate ligament resists the combined motions of anterior tibial translation and internal tibial rotation, which defines the concept of rotational stability. This function prevents anterior tibial subluxation of the lateral and medial tibiofemoral compartments that accounts for the pivot-shift phenomena. The placement of single anterior cruciate ligament grafts high and proximal at the femoral attachment and posterior at the tibial attachment results in a vertical graft orientation. This graft placement results in a limited ability to provide rotational stability and is inferior when compared to a double-bundle graft procedure. Studies show that a more oblique single-graft orientation, in the sagittal and coronal plane, achieved from a central anatomic femoral and tibial location provides rotational stability similar to a double-bundle anterior cruciate ligament graft.

CONCLUSION

There exists insufficient experimental and clinical data to recommend the more complex double-bundle anterior cruciate ligament graft technique over a well-placed central anatomic single graft in terms of restoring knee rotational stability. Meticulous surgical technique for anterior cruciate ligament graft placement is necessary to avoid failure.

The use of eccentrically biased resistance exercise to mitigate muscle impairments following anterior cruciate ligament reconstruction: a short review

Background:

Novel interventions that can safely and effectively overload muscle early following anterior cruciate ligament reconstruction are needed to minimize atrophy and weakness that often becomes longstanding.

Evidence Acquisition:

Eccentrically induced forces can be safely applied during the early stages of rehabilitation following surgery and serve as a potent stimulus for increasing muscle size and strength.

Results:

Compared to a standard rehabilitation program, adding an early 12-week eccentric resistance-training program 3 weeks after anterior cruciate ligament reconstruction induces improvement in quadriceps and gluteus maximus volume at 15 weeks and at 1 year after surgery. Likewise, those who performed an eccentrically biased rehabilitation program also achieved greater improvements in quadriceps strength and hopping ability measured at 15 weeks and at 1 year after surgery.

Clinical Relevance:

There is potential to safely and feasibly perform eccentric contractions as part of a formal rehabilitation program following anterior cruciate ligament reconstruction.

Analysis of cyclops lesions after different anterior cruciate ligament reconstructions: a comparison of the single-bundle and remnant bundle preservation techniques

OBJECTIVE

The aim of this work was to compare the prevalence of cyclops lesions after anterior cruciate ligament reconstruction (ACLR) using the single-bundle and remnant bundle preservation techniques.

MATERIALS AND METHODS

One hundred consecutive patients, who had undergone postoperative MRI of the knee followed by arthroscopic ACLR with the remnant bundle preservation technique (R) between February 2007 and August 2010, were enrolled in this study. Thirty-six consecutive patients who underwent ACLR using the single-bundle technique (S) were also included in this study as a control group. The MR findings were scored based on the presence of pre-ACL graft lesion as 0, 1, 2, or 3 on the sagittal images. The sixty-one specimens by second-look surgery (20 in S, 41 in R) were pathologically examined.

RESULTS

The numbers of patients with scores of 0, 1, 2, and 3 were 1, 18, 14, and 3 in group S and 4, 60, 29, and 7, in group R, respectively. Of the 61 patients who underwent second-look surgery (20 in S, 41 in R), eight had a cyclops lesion (three in group S and five in group R). The prevalence of cyclops lesion was not significantly different in group R and group S (p = 0.761).

CONCLUSIONS

The prevalence of a cyclops lesion was similar in both groups.

Anterior cruciate ligament injuries: anatomy, physiology, biomechanics, and management

OBJECTIVE

Anterior cruciate ligament (ACL) injuries are the most common ligament injury in the United States. These injuries can be career ending for athletes and severely disabling for all individuals. Our objectives are to review the epidemiology of these injuries, as well as ACL biomechanics, anatomy, and nonsurgical and surgical management so that generalists as well as sports medicine physicians, orthopedists, and others will have a better understanding of this serious injury as well as choices in its management.

DATA SOURCES

PubMed was used to identify relevant articles. These articles were then used to identify other sources.

MAIN RESULTS

Anterior cruciate ligament injuries occur more commonly in women than in men due to a variety of anatomical factors. The ACL consists of 2 major bundles, the posterolateral and the anteromedial bundles. Forces transmitted through these bundles vary with knee-joint position. Some patients with ACL injuries may not be candidates for surgery because of serious comorbid medical conditions. However, without surgical repair, the knee generally remains unstable and prone to further injury. There are a variety of surgical decisions that can influence outcomes. Single-bundle versus double-bundle repair, whether to leave the ruptured ACL remnant in the knee, the selection of the graft tissue, graft placement, and whether to use the transtibial, far anteromedial portal, or tibial tunnel-independent technique are choices that must be made.

CONCLUSIONS

With a sound knowledge of the anatomy and kinetics of the knee, newer improved surgical techniques have been developed that can restore proper knee function and have allowed many athletes to resume their careers. These new techniques have also limited the disability in nonathletes.

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.

ANATOMICAL RECONSTRUCTION OF ANTERIOR CRUCIATE LIGAMENT OF THE KNEE: DOUBLE BAND OR SINGLE BAND?

OBJECTIVE

To evaluate the double-band and single-band techniques for anatomical reconstruction of the anterior cruciate ligament of the knee and demonstrate that the double-band technique not only provides greater anterior stability but also causes less pain and a better subjective patient response.

METHODS

We selected 42 patients who underwent anterior cruciate ligament reconstruction, by means of either the single-band anatomical reconstruction technique, using flexor tendon grafts with two tunnels, or the double-band anatomical reconstruction technique, using four tunnels and grafts from the semitendinosus and gracilis tendons. All fixations were performed using interference screws. There was no variation in the sample. Before the operation, the objective and subjective IKDC scores, Lysholm score and length of time with the injury were evaluated. All these variables were reassessed six months later, and the KT-1000 correlation with the contralateral knee was also evaluated.

RESULTS

There was no significant difference between the two groups in subjective evaluations, but the single-band group showed better results in relation to range of motion and objective evaluations including KT-1000 (with statistical significance).

CONCLUSION

Our study demonstrated that there was no difference between the two groups in subjective evaluations, but better results were found using the single-band anatomical technique, in relation to objective evaluations.

Accidental perforation of the lateral femoral cortex in ACL reconstruction: an investigation of mechanical properties of different fixation techniques

PURPOSE

The aim of this study was to evaluate the mechanical properties of anterior cruciate ligament (ACL) reconstruction using the medial portal technique with cortical fixation and hybrid fixation after penetration of the lateral cortex by use of different drill sizes.

METHODS

In this biomechanical study a porcine in vitro model was used. The testing protocol consisted of a cyclic loading protocol (1,000 cycles, 50 and 250 N) and subsequent ultimate failure testing. Number of cyclic loadings survived, stiffness, yield load, maximum load, and graft elongation, as well as failure mode, were analyzed after ACL reconstruction with 5- to 9-mm soft-tissue grafts. In the control group, conventional penetration of the lateral cortex with a 4.5-mm drill and cortical fixation were performed. In the tested groups, the lateral cortex was penetrated with a drill matching the graft size. In the first part of the study, we used cortical fixation. In the second part, we used hybrid fixation with an interference screw.

RESULTS

In the first part of the study, ACL reconstruction with 5- to 6-mm perforation of the lateral cortex showed no significant differences in ultimate failure load after cyclic loading compared with the control group (P > .05). Specimens with reconstruction with 7- to 9-mm perforation of the lateral cortex and cortical fixation did not survive the cyclic loading protocol. In the second part of the study, with a hybrid fixation technique, ultimate failure testing after cyclic loading of specimens with 7- to 9-mm penetration showed no significant differences in tested parameters compared with the control group (P > .05).

CONCLUSIONS

After penetration of the lateral cortex with a drill size of more than 6 mm, cortical ACL fixation results in poor mechanical properties. Hybrid fixation increases the mechanical properties significantly after penetration with a 7- to 9-mm drill.

CLINICAL RELEVANCE

We advise caution to avoid penetration of the lateral femoral cortex when using cortical flip-button fixation. In case of accidental perforation of the lateral cortex with a diameter greater than 6 mm, we recommend performing hybrid fixation.

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.

Triple-bundle ACL grafts evaluated by second-look arthroscopy

PURPOSE

The purpose of this study was to evaluate the morphology of transplanted triple-bundle anterior cruciate ligament (ACL) grafts by second-look arthroscopy.

METHODS

The subjects were 41 patients with a mean age of 25.5 ± 8.5 years who underwent second-look arthroscopy at between 6 and 22 months after the anatomical triple-bundle ACL reconstruction using semitendinosus tendon autograft. Lachman test was negative in 38 knees and mildly positive with a firm endpoint in 3 knees. Arthroscopic evaluation of grafts was performed for the anteromedial graft (AM), the intermediate graft (IM), and the posterolateral graft (PL), focusing on tension and graft damage.

RESULTS

All grafts showed "fan-out" shape approaching the tibial attachment, which looked closer to the natural ACL compared to the double-bundle grafts. As to graft tension, 93% of AM, 90% of IM, and 88% of PL grafts were evaluated as taut, respectively. As to graft damage, there was no apparent rupture in the AM and IM grafts, while complete or substantial rupture was observed in 10% of PL grafts around the femoral tunnel aperture. The incidence of graft rupture in PL grafts was significantly greater than those in the AM and IM grafts. As to synovial coverage, 76% of AM, 78% of IM, and 59% of PL grafts were evaluated as "Good," while 41% of PL grafts were not fully covered with synovium. All of the synovial defects were observed around the femoral tunnel aperture.

CONCLUSION

The morphology of the triple-bundle grafts resembled that of the natural ACL, while complete or substantial rupture was observed in 10% of the PL grafts.

LEVEL OF EVIDENCE

Study of case series with no comparison group, Level IV.

The arrangement and the attachment areas of three ACL bundles

PURPOSE

Normal anterior cruciate ligament (ACL) can be divided into three fiber bundles-i.e., anteromedial (AM), intermediate (IM), and posterolateral (PL) bundles. However, their arrangement and attachment areas had remained unclear. The purpose of this study was to clarify the arrangement of these three ACL fiber bundles and their attachment sites, and to provide information on the tunnel placement in anatomical triple bundle ACL reconstruction.

METHODS

Seven non-embalmed human frozen knees were used. ACL fibers were bluntly divided into three bundles. A different-colored thread was wound around each fiber bundle in a spiral. Macroscopical investigation was performed to clarify the arrangement of three ACL bundles. Each fiber bundle was carefully detached from the femur and tibia, and then the distribution of attachment sites of each fiber bundle was observed.

RESULTS

In knee extension, all bundles consisting of AM, IM and PL bundles ran parallel to each other in the lateral view from the medial side. The AM bundle overlapped with the IM bundle, whereas the PL bundle ran parallel to them on the distal aspects. As the knee flexion increased, the bundles became twisted around each other. On the tibial side, the attachment areas of three fiber bundles formed a triangular shape showing arrangements of AM, IM and PL bundles on the anteromedial, anterolateral and posterior aspects, respectively. On the femoral side, the PL bundle was attached on the distal-posterior areas; the IM bundle was attached distal-anterior to the AM bundle. They were arranged in a triangular shape on the tibia side as well.

CONCLUSION

This study clarified the arrangement of three fiber bundles of ACL and detailed geographical locations of their attachment sites. The detailed anatomic description of the natural ACL attachment might suggest to surgeons where to make tunnels during anatomical double/triple bundle ACL reconstruction.

Clinical results of technique for double bundle anterior cruciate ligament reconstruction using hybrid femoral fixation and Retroscrew

Background

Anatomic anterior cruciate ligament (ACL) reconstruction has been presented as a means to more accurately restore the native anatomy of this ligament. This article describes a new method that uses a double bundle to perform ACL reconstruction and to evaluate the clinical outcome.

Methods

Grafts are tibialis anterior tendon allograft for anteromedial bundle (AMB) and hamstring tendon autograft without detachment of the tibial insertion for posterolateral bundle (PLB). This technique creates 2 tunnels in both the femur and tibia. Femoral fixation was done by hybrid fixation using Endobutton and Rigidfix for AMB and by biointerference screw for PLB. Tibial fixations are done by Retroscrew for AMB and by native insertion of hamstring tendon for PLB. Both bundles are independently and differently tensioned. We performed ACL reconstruction in 63 patients using our new technique. Among them, 47 participated in this study. The patients were followed up with clinical examination, Lysholm scales and International Knee Documentation Committee (IKDC) scoring system and radiological examination with a minimum 12 month follow-up duration.

Results

Significant improvement was seen on Lachman test and pivot-shift test between preoperative and last follow-up. Only one of participants had flexion contracture about 5 degrees at last follow-up. In anterior drawer test by KT-1000, authors found improvement from average 8.3 mm (range, 4 to 18 mm) preoperatively to average 1.4 mm (range, 0 to 6 mm) at last follow-up. Average Lysholm score of all patients was 72.7 ± 8.8 (range, 54 to 79) preoperatively and significant improvement was seen, score was 92.2 ± 5.3 (range, 74 to 97; p < 0.05) at last follow-up. Also IKDC score was normal in 35 cases, near normal in 11 cases, abnormal in 1 case at last follow-up.

Conclusions

Our new double bundle ACL reconstruction technique used hybrid fixation and Retroscrew had favorable outcomes.

Mechanical functions of the three bundles consisting of the human anterior cruciate ligament

PURPOSE

The reconstruction technique to individually reconstruct multi-bundles of the anterior cruciate ligament (ACL) has been improved in the last decade. For further improvement of the technique, the present study was conducted to determine the force sharing among the three bundles (the medial and lateral bundles (AMM and AML) of the anteromedial (AM) bundle and the posterlateral (PL) bundle) of the human ACL in response to hyperextension, passive flexion-extension and anterior force to the knee.

METHODS

Using a 6-DOF robotic system, the human cadaveric knee specimens were subjected to hyperextension, passive flexion-extension and anterior-posterior tests, while recording the 6-DOF motion and force/moment of the knees. The intact knee motions recorded during the tests were reproduced after sequential bundle transection to determine the bundle forces.

RESULTS

The bundle forces were around 10 N at 5 N-m of hyperextension and remained less than 5 N during passive flexion-extension. In response to 100 N of anterior force, the AMM and PL bundle forces were slightly higher than the AML bundle force at full extension. The AMM bundle force remained at a high level up to 90° of flexion, with significant differences versus the AML bundle force at 15°, 30° and 60° of flexion and the PL bundle force at 90° of flexion.

CONCLUSION

The AMM bundle is the primary stabilizer to tibial anterior drawer through wide range of motion, while the AML bundle is the secondary stabilizer in deep flexion angles. The PL bundle is the crucial stabilizer to hyperextension as well as tibial anterior drawer at full extension.

Peri-anterior cruciate ligament reconstruction femur fracture: a biomechanical analysis of the femoral tunnel as a stress riser

PURPOSE

Sixteen case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential stress riser for fracture formation. Additionally, double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the significance of a stress riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a stress riser for fracture and that this effect increases with the size of the tunnel (8 mm vs. 10 mm) and with the number of tunnels (1 vs. 2).

METHODS

Femoral tunnels simulating single bundle (SB) hamstring graft (8 mm), bone-patellar tendon-bone graft (10 mm), and double bundle (DB) ACL reconstruction (7, 6 mm) were drilled in fourth-generation saw bones. These three experimental groups and a control group consisting of native saw bones without tunnels were loaded to failure.

RESULTS

All fractures occurred through the tunnels in the DB group, whereas fractures did not consistently occur through the tunnels in the SB groups. The mean fracture load was 6,145N ± 471N in the native group, 5,691N ± 198N in the 8 mm SB group, 5,702N ± 282N in the 10 mm SB group, and 4,744N ± 418N in the DB group. The mean fracture load for the DB group was significantly lower when compared to the native, 8 mm SB, and 10 mm SB groups independently (P value = 0.0016, 0.0060, and 0.0038, respectively). The mean fracture loads for neither SB groups were not significantly different from the native group.

CONCLUSIONS

An anatomically placed femoral tunnel in single bundle ACL reconstruction in our experimental model was not a significant stress riser to fracture, whereas the two femoral tunnels in double bundle ACL reconstruction significantly decreased load to failure. The results support the sparsity of reported peri-ACL reconstruction femur fractures in single femoral tunnel techniques. However, the increased fracture risk in double bundle ACL reconstruction may be a cause for concern and impact patient selection.

A matched pairs comparison of single- versus double-bundle anterior cruciate ligament reconstructions, clinical results and manual laxity testing

PURPOSE

To compare the subjective clinical results as well as manual anterior and rotational stability in patients treated with either single- (SB) or double-bundle (DB) anterior cruciate ligament (ACL) reconstructions.

METHODS

Sixty-four patients who had undergone SB or DB hamstring ACL reconstruction with hamstrings were included in a retrospective matched pair analysis. At follow-up IKDC subjective, CKS, KOOS, CKS and a visual analogue satisfaction scale was assessed. A blinded surgeon examined the joint laxity and completed the objective IKDC. The KT-1000 was used to bilaterally test anterior tibial translation. Patients with confounding variables, which statistically influenced the clinical outcome (passive flexion and extension deficits, persistent quadriceps deficit, tibiofemoral osteoarthritis and non-repairable medial meniscus injury), were identified and excluded from the statistical analysis (n = 10).

RESULTS

For all subjective scores, DB patients reported increased scores compared with SB patients. While consistently higher scores were demonstrated, statistical significance was only achieved for the IKDC subjective (P = 0.04) and VAS satisfaction (P = 0.02). Graded stability results of the Lachman, anterior drawer and pivot-shift tests were significantly higher in the DB group and KT-1000 side-to-side difference was significantly better for DB (P = 0.01).

CONCLUSION

DB ACL reconstruction appeared to more consistently result in significantly higher subjective outcome scores and manual tests of joint stability than SB ACL reconstruction. Besides the surgical technique, normal extension and quadriceps strength after surgery were identified to be an essential component in order to provide the patient with a successful outcome.

Outcomes and second-look arthroscopic evaluation after double-bundle anterior cruciate ligament reconstruction with use of a single tibial tunnel

BACKGROUND

The correlation between graft appearance and clinical outcome after double-bundle anterior cruciate ligament (ACL) reconstruction is a major concern. In this study, the graft appearance was assessed with use of second-look arthroscopy and was correlated with the clinical outcome. Overall clinical outcomes after double-bundle ACL reconstruction with use of a single tibial tunnel were analyzed.

METHODS

Thirty-seven knees that underwent second-look arthroscopy after double-bundle ACL reconstruction and sixty-two knees that underwent double-bundle ACL reconstruction without subsequent second-look arthroscopy were included in this retrospective study. The ninety-nine patients enrolled were followed for thirty-five months (range, twenty-four to fifty-eight months), and the mean duration from ACL reconstruction to second-look arthroscopy was twenty-five months (range, twelve to thirty-six months). Graft thickness, apparent graft tension, and synovial coverage were graded during second-look arthroscopy. Correlations were sought between graft appearance and Lysholm knee scores, International Knee Documentation Committee (IKDC) grades, anterior laxity, and pivot-shift test results.

RESULTS

Postoperatively, ninety-four (94.9%) of the ninety-nine knees had an IKDC rating of B or higher, mean anterior laxity was 1.29 mm (range, 0 to 6 mm), and ninety-two knees (92.9%) had a negative pivot-shift result. With regard to graft thickness and tension, anteromedial bundles were graded as A in twenty-eight (75.7%) of the thirty-seven second-look knees and as B in nine knees (24.3%). Posterolateral bundles were graded as A in twenty-five knees (67.6%), B in six knees (16.2%), and C in six knees (16.2%). With regard to synovial coverage, anteromedial bundles were graded as C in only two knees (5.4%) and posterolateral bundles were graded as C in six knees (16.2%). No correlation was found between graft appearance and clinical outcome.

CONCLUSIONS

In the present study, we observed that clinical outcomes were as satisfactory with a single tibial tunnel as with two tibial tunnels. However, more tears and poorer synovial coverage were observed for posterolateral than for anteromedial bundles during second-look arthroscopy. No significant correlation was found between graft appearance and clinical outcome.

Using magnetic resonance imaging to predict adequate graft diameters for autologous hamstring double-bundle anterior cruciate ligament reconstruction

PURPOSE

To determine whether the preoperative magnetic resonance imaging (MRI) cross-sectional area (CSA) of the hamstring tendons can predict intraoperative bundle diameters during double-bundle anterior cruciate ligament reconstruction.

METHODS

A prospective study of 34 patients undergoing anterior cruciate ligament reconstruction with hamstring autografts was performed. CSAs of independent and combined hamstring tendon diameters were correlated to preoperative magnetic resonance images.

RESULTS

Intraoperative tendon diameter measurement positively correlated with preoperative MRI tendon CSA measurement for gracilis (P = .0006), semitendinosus (P = .001), and final graft size (P = .001). Double-stranded gracilis grafts greater than or equal to 5 mm in diameter had a mean preoperative MRI gracilis CSA of 9.98 mm(2) compared with a mean of 7.76 mm(2) for grafts less than 5 mm (P = .002). Double-stranded semitendinosus grafts greater than or equal to 6 mm had a mean preoperative MRI tendon CSA of 17.33 mm(2) compared with 14.80 mm(2) for grafts less than 6 mm (P = .02). Final grafts of diameter greater than or equal to 7 mm had a mean preoperative MRI total tendon CSA of 26.54 mm(2) compared with 22.22 mm(2) for grafts under 7 mm (P = .06).

CONCLUSIONS

Preoperative MRI is a clinically useful tool to assess hamstring tendon graft diameter. We recommend preoperative CSA threshold values of 10 mm(2) and 17 mm(2) for the gracilis and semitendinosus tendons, respectively, to reliably predict the potential for a double-bundle anterior cruciate ligament reconstruction.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

The effect of graft fixation sequence on force distribution in double-bundle anterior cruciate ligament reconstruction

PURPOSE

This paper investigated the effect of graft fixation sequence on knee joint biomechanics after a double-bundle ACL reconstruction.

METHOD

Two independently published biomechanical studies that investigated the biomechanics of double-bundle ACL reconstructions using similar robotic testing systems were compared. In each study, ten human cadaveric knees were tested under three different conditions: intact, ACL deficient, and ACL reconstructed using a double-bundle technique with the anteromedial (AM) graft fixed at 60° of flexion and the posterolateral (PL) graft fixed at full extension. In one study (Study A), the AM graft was fixed first; while in another study (Study B), the PL graft was fixed first. Knee kinematics, in situ forces of the ACL and the ACL grafts were measured under two loading conditions: an anterior tibial load of 134 N and a combined tibial torques (10 N·m valgus and 5 N·m internal tibial torques) in both studies.

RESULT

When AM graft was fixed first, the in situ force of the AM graft was lower than the native AM bundle at all flexion angles. The in situ force in the PL graft, however, was higher than the native PL bundle at all flexion angles. When the PL graft was fixed first, the in situ force of the AM graft was higher than the native AM bundle, while the in situ forces of the PL graft were lower than the native PL bundle at all flexion angles. Both studies demonstrated that the double-bundle ACL reconstructions can closely restore the normal knee joint kinematics.

CONCLUSION

Even though the grafts were fixed using similar initial tensions and at same flexion angles, the sequence of fixing the two grafts in a double-bundle ACL reconstruction could alter the in situ forces in the grafts and affect the knee kinematics. These data imply that in clinical application of a double-bundle ACL reconstruction, the sequence of graft fixation should be an important surgical parameter.

Avoiding tunnel collisions between fibular collateral ligament and ACL posterolateral bundle reconstruction

PURPOSE

The purpose of this study was to evaluate the risk of tunnel collisions of the fibular collateral ligament (FCL) and posterolateral bundle anterior cruciate ligament (PLB-ACL) tunnels during a combined FCL and double-dundle (DB) ACL reconstruction.

METHODS

Thirty-six 4th-generation synthetic femurs (Sawbones, Pacific Research Laboratories, Vashon, WA) were utilized, and two different femur sizes were used. A FCL tunnel and a PLB-ACL tunnel were reamed on each femur. The tunnels of synthetic specimens that did not have a collision were filled with an epoxy resin augmented with BaSO(4) and radiographic evaluation, and Multidetector CT exams of the specimens were performed.

RESULTS

The rate of tunnel collision when the FCL tunnel was reamed to a depth of 30 mm was 75 and 69.4% for the 25 mm depth. There was a significantly increased risk of tunnel collision when the FCL tunnel was reamed proximally with coronal angulations of 20° and 40°. No collisions were noted when the FCL tunnel was reamed parallel to the distal condylar line and with axial angulations of 20° and 40°.

CONCLUSION

This study provides new insight into tunnel positioning during a combined FCL and DB-ACL reconstruction. The results show that a concomitant FCL injury do not represent a contraindication to perform a DB-ACL reconstruction as long as the FCL tunnel is reamed with no proximal angulation and is directed anteriorly with an axial angulation between 20° and 40°.

Does Vitamin E and C Supplementation Improve the Recovery From Anterior Cruciate Ligament Surgery?

Muscular (quadriceps) weakness is a predominant impairment that follows anterior cruciate ligament injury and surgery. This continued weakness impairs activities of daily living and could predispose patients to adverse conditions later in life, such as knee osteoarthritis. Vitamins E and C have potent antioxidant and anti-inflammatory activity. Herein, the authors summarize the state-of-the science and suggest directions for future research endeavors regarding the therapeutic influence of vitamins E and C, or other antioxidants, on the recovery from anterior cruciate ligament injury and surgery.

Double-bundle ACL reconstruction demonstrated superior clinical stability to single-bundle ACL reconstruction: a matched-pairs analysis of instrumented tests of tibial anterior translation and internal rotation laxity

PURPOSE

To compare objective measures of in vivo joint laxity between patients treated with single-bundle (SB) or double-bundle (DB) anterior cruciate ligament (ACL) reconstructions.

METHODS

Sixty-four patients matched by age, height, weight, and that had undergone unilateral SB or DB hamstring ACL reconstruction participated in this study. Bilateral anterior tibial translation (ATT) was recorded using the KT1000 arthrometer, and a robotic testing system was used to assess side-to-side differences in rotational characteristics. Each reconstruction was evaluated to determine how well it mimicked the anteroposterior (AP) and rotational biomechanics of the normal knee. A reconstruction was defined as mimicking the normal knee if ATT and internal rotation (IR) were within 3 mm and 3.5°, respectively.

RESULTS

Side-to-side differences in ATT were significantly higher for the SB group (2.2 ± 1.4 mm) than the DB group (1.1 ± 1.0 mm, P = 0.001). While relative side-to-side differences in IR did not differ between the SB (1.3°) and DB groups (1.1°, P = 0.82), absolute IR differences were significantly less with the DB reconstruction (2.1° vs. 4.7°, P = 0.001). A significantly greater percentage of DB patients (81%, P = 0.0003) had both ATT and IR similar to the normal knee, compared to 34% of the SB patients; however, IKDC subjective scores did not differ between groups. Regardless of technique, patients with the greatest rotational laxity of their non-operative knee demonstrated significantly worse IKDC scores.

CONCLUSION

DB reconstruction resulted in reduced side-to-side differences in both ATT and IR. The DB technique more consistently reproduced the biomechanical profile of the uninjured limb than did the SB technique without increasing the risk of over-constraining the knee.

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.

ACL reconstruction with double-bundle technique: a review of clinical results

Anatomical and biomechanical studies have shown that the anterior cruciate ligament (ACL) primarily consists of 2 distinct bundles, the anteromedial (AM) and posterolateral (PL), which act separately during the knee's range of motion. Conventional ACL reconstruction techniques have focused on restoration of the AM bundle only, while giving limited attention to the PL bundle. The outcomes of these single-bundle techniques have been relatively good in ACL reconstruction. In recent years, many authors have developed double-bundle ACL reconstruction techniques to better replicate ACL anatomy and its 2 bundles. The purpose of this article is to analyze the clinical results of the double-bundle ACL reconstruction according to the current literature. The review focuses primarily on randomized controlled trials. According to the 14 randomized controlled trials published in the literature and included in this review, 4 (29%) trials did not find any significant differences in the results between double-bundle and single-bundle ACL reconstruction. Ten (71%) trials reported significantly better results with double-bundle technique than with single-bundle technique, of which 7 (50%) reported better rotational stability, 6 (43%) reported better anterior stability, 3 (21%) reported better objective knee scores, 3 (21%) reported better subjective knee scores, 2 (14%) reported fewer graft failures, and 1 (7%) reported less degenerative changes of the knee. In addition, none of the trials found the single-bundle technique to have better results in any of these evaluations when compared with the double-bundle technique. However, 13 (93%) of the 14 trials had only a short-term follow-up (1-3 years), and only 1 (7%) trial conducted long-term follow-up (8-10 years). Therefore, only through long-term follow-up studies will we be able to determine whether the double-bundle reconstruction is really better than the single-bundle technique.

Effect of patient age on morphology of anterior cruciate ligament grafts at second-look arthroscopy

PURPOSE

The purpose of this study was to evaluate the effect of patient age on the morphology of anterior cruciate ligament (ACL) graft after ACL reconstruction, as well as to investigate the relation between morphology and clinical outcomes.

METHODS

Anatomic double-bundle ACL reconstruction by use of autogenous semitendinosus tendon graft was performed in 193 patients. Of these, 102 patients (51 male and 51 female patients) had consented to undergo second-look arthroscopy at the time of hardware removal within 2 years of ACL reconstruction. These patients were divided into the following 3 groups according to their age: group A, 29 years or younger (55 cases); group B, 30 to 49 years (36 cases); and group C, 50 years or older (11 cases). At second-look arthroscopy, the grafts were evaluated based on synovial coverage around the grafts, tension, and damage/tear of the grafts themselves. Clinical outcomes were evaluated with a physical examination including the Lachman test and side-to-side difference by KT-2000 knee arthrometer (MEDmetric, San Diego, CA), subjective assessment including International Knee Documentation Committee subjective assessment and Lysholm score, and sports activity level including Tegner activity scale. The Mann-Whitney U test, Kruskal-Wallis test, analysis of variance, and χ² test were used for statistical analysis.

RESULTS

Good synovial coverage over the graft was found in 49 cases (89%) in group A, 30 (83%) in group B, and 5 (46%) in group C. Synovial coverage in group C was significantly poorer than that in the other 2 groups. No statistical difference was found in tension of graft among the 3 groups, whereas the incidence of a "partial tear" tended to increase with age. With respect to clinical outcome, there was no significant difference among the 3 groups except for sports activity.

CONCLUSIONS

Although clinical outcomes were comparable among the 3 groups, synovial coverage of ACL grafts in elderly patients was significantly poorer than that in younger patients.

LEVEL OF EVIDENCE

Level II, prognostic study.

ACL reconstruction in sports active people: transtibial DB technique with ST/G vs. transtibial SB technique with BPTB: preliminary results

The single-bundle ACL reconstruction ensures good outcomes and it is a well-established and widespread technique. Nevertheless, some patients still present residual pain and instability. Recent studies have showed that the double-bundle technique restores better natural ACL-fitting kinematics. Long-term clinical studies comparing the two surgical techniques are not frequent and there is no instrument to evaluate function and kinematics during the knee rotation in vivo. In this randomised prospective study performed on sportive people, we compare the BPTB single-bundle ACL reconstruction technique, which is the most common surgical technique performed on these patients' category, with the ACL double-bundle reconstruction technique (DB), in order to evaluate possible differences between the groups. Comparing the two groups, no statistically significant difference regarding the post-operative Lysholm score (p=0.368) the Tegner activity scale (p=0.519) and the arthrometric evaluation with KT-1000 (p=0.74) have been observed. On the contrary, the IKDC evaluation showed a statistically significant difference (p=0.004) better results of the DB group. Moreover, as assessed by the Tegner activity scale, only patients of the DB group were able to return to sports at a pre-injury level. Our data suggest that the double bundle ST/G ACL reconstruction technique results into slightly better outcome than the traditional technique of single-bundle BPTB. The verification and quantification of the advantages of this technique is anticipated with future studies focusing to the accurate measurement of knee rotation during different activities.

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.

Energy absorbed by longitudinally splitting a tibialis anterior allograft: implications for double-bundle anterior cruciate ligament reconstruction

PURPOSE

Split tibialis anterior (TA) allografts have been proposed as a source for double-bundle anterior cruciate ligament reconstruction. We sought to determine whether longitudinally splitting a TA tendon leads to a change in the mechanical properties of the tendon.

METHODS

Seven cadaveric matched pairs of TA tendons were procured. One member of each pair was longitudinally pierced in its midportion and then bluntly split, creating 2 longitudinally divided grafts. The other member of the pair remained intact. Each tendon was then frozen into thermoelectrically cooled clamps and loaded to failure on an MTS machine (MTS Systems, Eden Prairie, MN) at a displacement of 1 mm/s. The area under the force-versus-displacement curve was calculated as an indicator of energy absorbed by the tendon before failure. The energy absorbed by the intact tendon was then compared with the summed energy absorbed by the 2 specimens obtained by splitting the sibling specimen.

RESULTS

Energy absorbed by the intact tendon was 10,300 +/- 3,433 Nmm, whereas total energy absorbed by the 2 longitudinally split tendons was 10,530 +/- 2,095 Nmm (P = .78).

CONCLUSIONS

Longitudinal splitting of a TA allograft by the technique described does not significantly affect the graft's ability to absorb energy.

CLINICAL RELEVANCE

The splitting technique described can safely be used to create 2 grafts if surgeons wish to use a TA graft for a double-bundle anterior cruciate ligament reconstruction or for reconstruction by use of fixation devices requiring 2 looped tendon grafts.