Anatomical single bundle anterior cruciate ligament reconstruction

Application of Nondegradable Synthetic Materials for Tendon and Ligament Injury

Tendon and ligament injuries, prevalent requiring surgical intervention, significantly impact joint stability and function. Owing to excellent mechanical properties and biochemical stability, Nondegradable synthetic materials, including polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE), have demonstrated significant potential in the treatment of tendon and ligament injuries. These above materials offer substantial mechanical support, joint mobility, and tissue healing promotion of the shoulder, knee, and ankle joint. This review conclude the latest development and application of nondegradable materials such as artificial patches and ligaments in tendon and ligament injuries including rotator cuff tears (RCTs), anterior cruciate ligament (ACL) injuries, and Achilles tendon ruptures.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

I.

Rotational Stability of the Knee in a Comparative Study of Anterior Cruciate Ligament Reconstruction Using the Double-Bundle and Single-Bundle Techniques

BACKGROUND

The purpsose of this study was to evaluate the biomechanical outcomes of patients who underwent ACL reconstruction either with the DB or SB technique. We hypothesized that the DB technique would provide better rotation control of the knee following ACL reconstruction.

METHODS

The study included seventy-five participants (26 DB, 22 SB, and 27 healthy volunteers). Only cases with at least one year of postoperative follow-up were included. The participants performed three different demand tasks: walk task, walk and change direction, and stair descent and change direction, which was tracked using a three-dimensional 4-camera optoelectronic system. The following kinematic data were analyzed: tibial rotation amplitude and maximal internal and external rotation. Knees with ACL reconstruction were compared to contralateral knees with intact ACL and healthy knees. Clinical outcomes were determined using the subjective and objective International Knee Documentation Committee (IKDC) questionnaire and a manual arthrometer (KT 1000).

RESULTS

Both surgical groups exhibited similar clinical outcomes (mean subjective IKDC 91 SB vs. 90 DB, P=0.815; KT 1000 difference: 2mm in both groups, P=0.772). The vertical component of the ground force reaction revealed no differences between the surgical and control groups (P>0.05). Tibial rotation amplitude and maximal internal and external rotation were similar between the control, SB, and DB groups in all three different demand tasks (P>0.05).

CONCLUSION

ACL reconstruction using either the SB or DB technique can restore rotational control to the level of a healthy knee. No clinical or functional differences were found between the SB and DB surgical options.

Comparative Analysis of Arthroscopic Tight Rope ACL Reconstruction Using four Strand Isolated Semitendinosus Graft and Quadrupled Combined Hamstring Graft

BACKGROUND

Arthroscopic ACL reconstruction using hamstring autograft is a quite a popular surgical procedure. But there is a conflict regarding the use of isolated semitendinosus graft or a combined hamstring graft. We did a comparative analysis of the functional outcome after ACL reconstruction performed with four strand semitendinosus graft and a combined hamstring graft over tightrope.

METHODS

Two groups of 30 patients each with similar demographic profiles, presenting with symptoms of instability after chronic ACL tear were included. A standard single bundle arthroscopic ACL reconstruction was performed by using four-strand semitendinosus graft in Group A and combined hamstring graft in Group B patients. Clinical and functional outcome analysis was done using quantitative anterior tibial translation measurement and Lysholm score.

RESULTS

The mean age of subjects in group A was 29 years and in Group B was 28 years. The semitendinosus graft length was insufficient in 13.33% cases in group A. The improvement in Lysholm score and the decrease in the tibial translation were comparable in both the groups at one year of follow-up. No added comorbidities were noted in additional removal of gracilis tendon in group B patients.

CONCLUSION

Isolated semitendinosus four-strand autograft can be used for arthroscopic single bundle ACL reconstruction when adequate graft length is obtained. However, one should not be hesitant in additional removal of gracilis tendon when needed. In terms of functional outcome and patient satisfaction, both the graft configurations stand the same.

Establishment of near and non isometric anterior cruciate ligament reconstruction with artificial ligament in a rabbit model

Background

Tunnel position deicide the isometry of graft attachment in synthetic anterior cruciate ligament (ACL) reconstruction. Near-isometric tunnel position may have advantage in graft integration and knee function in ACL reconstruction (ACLR) with polyethylene terephthalate (PET) ligament. Few studies focused on tunnel position isometry when conduct ACLR with an animal model. This study aimed to establish a preclinical rabbit model of near and non isometric ACLR with PET ligament and investigate the advantage of near-isometric ACLR compared to non-isometric ACLR.

Methods

Nine hind limbs of rabbit were used in tunnel position study. Two femoral(anatomic, nonanatomic) tunnels and three tibial(anterior, middle, posterior) tunnels were used to measure tunnel position isometry during knee full range of motion. The tunnel position combination with minimal isometry was considered as near-isometric tunnel position. Then, 48 rabbits divided into two groups were conducted near or non isometric ACLR with PET ligament with graft fixation angle of 30° and constant tension of 5N. PET ligament isometry, range of motion(ROM) restriction, knee laxity were recorded after operation and followed up with macroscopic observation, microcomputed tomography (micro-CT) analysis, histology assessment and biomechanical test at 4 and 8 weeks postoperatively.

Results

The tunnel combination with minimal isometry was femoral anatomic position and tibial posterior position(5.19 ​± ​1.78%) and considered as near-isometric tunnel position. ROM restriction were observed in non-isometric group (22.50 ​± ​14.14°) while none in near-isometric group. However, no ROM restriction observed at 8 weeks in both group. Knee laxity compared to contralateral knee were better in near-isometric group than non-isometric group (stable/slack/total 10/2/12 VS 3/9/12, p ​= ​0.012) at 8 weeks postoperatively. Supeiror PET ligament integration were also observed in near-isometric group through macroscopic observation, micro-CT analysis, histology assessment at both 4 and 8 weeks. The failure load in the Near-Isometric group at 8 weeks were higher than timezero reconstruction with statistical difference (156.8N ​± ​25.98N vs.102.6 ​± ​22.96N, p ​= ​0.02).

Conclusion

A rabbit model of ACLR based on tunnel position isometry was successfully established in this study. The near-isometric tunnel position in rabbit model was femoral anatomic position and tibial posterior position. A near-isometric ACLR with PET ligament did not cause ROM restriction and had a better graft integration and follow-up stability than non-isometric ACLR with ROM restriction.

The Translational Potential of this Article

The study demonstrate the establishmentof near-isometric tunnel position and non-isometric tunnel position with significant difference of ROM restriction and graft-bone integration. The described tunnel positions with differential isometry in a rabbit ACLR provides a reproducible and translational small animal model and enables preclinical research between tunnel position isometry and its affection on variable grafts, graft integration and knee function.

Outcomes Following Arthroscopic Single and Double Bundle Anterior Cruciate Ligament (ACL) Reconstruction Supported by the Comprehensive Early Rehabilitation Program (CERP)

Background

The aim of this study was to compare the level of functional condition in patients who had rehabilitation with the comprehensive early rehabilitation program (CERP) following either single bundle (SB) or double bundle (DB) anterior cruciate ligament reconstruction (ACLR) using semitendinosus-gracilis tendon graft (ST-G) method. We hypothesized that 12 weeks after reconstruction followed by a rehabilitation program, there would be a difference in clinical results and functional activity between patients.

Material/Methods

This study included 94 patients who had rehabilitation with CERP after knee surgery for a knee injury from a recreational sport. There were 49 patients in Group 1 (mean age, 36.5 years) who had CERP after SB ACLR, and 45 patients in Group 2 (mean age, 35.6 years) who had CERP after DB ACLR. Functional condition was tested using the Lysholm Knee Scoring Scale, and knee stability was measured using KT-2000. The first examination was performed before CERP and the second examination was performed 12 weeks later.

Results

The level of functional condition in both groups was similar before rehabilitation with CERP, with no significant difference (P<0.958) and was considered relatively low. In the second examination, 12 weeks after starting CERP, the patients improved in both groups. The improvement was larger in the SB ACLR Group 1 than in the DB ACLR Group 2. The difference was significant (P<0.005). However, the patients in Group 2 achieved better knee stability scores in the KT-2000 examination than the patients in Group 1. The difference was significant (P=0.035).

Conclusions

We found that the patients from both groups after 12 weeks of CERP achieved an improvement in stability and functional activity within normal limits. However, SB ACLR was more effective than DB ACLR in terms of the level of functionality achieved with CERP but was less effective in terms of knee stability.

Lateral Extra-articular Tenodesis Reduces Failure of Hamstring Tendon Autograft Anterior Cruciate Ligament Reconstruction: 2-Year Outcomes From the STABILITY Study Randomized Clinical Trial

BACKGROUND

Persistent anterolateral rotatory laxity after anterior cruciate ligament (ACL) reconstruction (ACLR) has been correlated with poor clinical outcomes and graft failure.

HYPOTHESIS

We hypothesized that a single-bundle, hamstring ACLR in combination with a lateral extra-articular tenodesis (LET) would reduce the risk of ACLR failure in young, active individuals.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

This is a multicenter, prospective, randomized clinical trial comparing a single-bundle, hamstring tendon ACLR with or without LET performed using a strip of iliotibial band. Patients 25 years or younger with an ACL-deficient knee were included and also had to meet at least 2 of the following 3 criteria: (1) grade 2 pivot shift or greater, (2) a desire to return to high-risk/pivoting sports, (3) and generalized ligamentous laxity (GLL). The primary outcome was ACLR clinical failure, a composite measure of rotatory laxity or a graft rupture. Secondary outcome measures included the P4 pain scale, Marx Activity Rating Scale, Knee injury Osteoarthritis and Outcome Score (KOOS), International Knee Documentation Committee score, and ACL Quality of Life Questionnaire. Patients were reviewed at 3, 6, 12, and 24 months postoperatively.

RESULTS

A total of 618 patients (297 males; 48%) with a mean age of 18.9 years (range, 14-25 years) were randomized. A total of 436 (87.9%) patients presented preoperatively with high-grade rotatory laxity (grade 2 pivot shift or greater), and 215 (42.1%) were diagnosed as having GLL. There were 18 patients lost to follow-up and 11 who withdrew (~5%). In the ACLR group, 120/298 (40%) patients sustained the primary outcome of clinical failure, compared with 72/291 (25%) in the ACLR+LET group (relative risk reduction [RRR], 0.38; 95% CI, 0.21-0.52; P < .0001). A total of 45 patients experienced graft rupture, 34/298 (11%) in the ACLR group compared with 11/291 (4%) in the ACL+LET group (RRR, 0.67; 95% CI, 0.36-0.83; P < .001). The number needed to treat with LET to prevent 1 patient from graft rupture was 14.3 over the first 2 postoperative years. At 3 months, patients in the ACLR group had less pain as measured by the P4 (P = .003) and KOOS (P = .007), with KOOS pain persisting in favor of the ACLR group to 6 months (P = .02). No clinically important differences in patient-reported outcome measures were found between groups at other time points. The level of sports activity was similar between groups at 2 years after surgery, as measured by the Marx Activity Rating Scale (P = .11).

CONCLUSION

The addition of LET to a single-bundle hamstring tendon autograft ACLR in young patients at high risk of failure results in a statistically significant, clinically relevant reduction in graft rupture and persistent rotatory laxity at 2 years after surgery.

REGISTRATION

NCT02018354 ( ClinicalTrials.gov identifier).

The Anatomic Centers of the Femoral and Tibial Insertions of the Anterior Cruciate Ligament: A Systematic Review of Imaging and Cadaveric Studies Reporting Normal Center Locations

BACKGROUND

The anterior cruciate ligament (ACL) is regularly reconstructed if knee joint function is impaired. Anatomic graft tunnel placement, often assessed with varying measurement methods, in the femur and tibia is considered important for an optimal clinical outcome. A consensus on the exact location of the femoral and tibial footprint centers is lacking.

PURPOSE

To systematically review the literature regarding anatomic centers of the femoral and tibial ACL footprints and assess the mean, median, and percentiles of normal centers.

STUDY DESIGN

Systematic review.

METHODS

A systematic literature search was performed in the PubMed/Medline database in November 2015. Search terms were the following: "ACL" and "insertion anatomy" or "anatomic footprint" or "radiographic landmarks" or "quadrant methods" or "tunnel placement" or "cadaveric femoral" or "cadaveric tibial." English-language articles that reported the location of the ACL footprint according to the Bernard and Hertel grid in the femur and the Stäubli and Rauschning method in the tibia were included. Weighted means, weighted medians, and weighted 5th and 95th percentiles were calculated.

RESULTS

The initial search yielded 1393 articles. After applying the inclusion and exclusion criteria, 16 studies with measurements on cadaveric specimens or a healthy population were reviewed. The weighted mean of the femoral insertion center based on measurements in 218 knees was 29% in the deep-shallow (DS) direction and 35% in the high-low (HL) direction. The weighted median was 26% for DS and 34% for HL. The weighted 5th and 95th percentiles for DS were 24% and 37%, respectively, and for HL were 28% and 43%, respectively. The weighted mean of the tibial insertion center in the anterior-posterior direction based on measurements in 300 knees was 42%, and the weighted median was 44%; the 5th and 95th percentiles were 39% and 46%, respectively.

CONCLUSION

Our results show slight differences between the weighted means and medians in the femoral and tibial insertion centers. We recommend the use of the 5th and 95th percentiles when considering postoperative placement to be "in or out of the anatomic range."

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

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

Comparison of graft bending angle during knee motion after outside-in, trans-portal and trans-tibial anterior cruciate ligament reconstruction

PURPOSE

To determine graft bending angle (GBA) during knee motion after anatomic anterior cruciate ligament (ACL) reconstruction and to clarify whether surgical techniques affect GBA. Our hypotheses were that the graft bending angle would be highest at knee extension and the difference of surgical techniques would affect the bending steepness.

METHODS

Eight healthy volunteers with a mean age of 29.3 ± 3.0 years were recruited and 3D MRI knee models were created at three flexion angles (0°, 90° and 130°). Surgical simulation of the tunnel drilling was performed with anatomic tunnel position using each outside-in (OI), trans-portal (TP) and trans-tibial (TT) techniques on the identical cases. The models were matched to other knee positions and the GBA in 3D was measured using computational software. Double-bundle ACL reconstruction was analysed first, and single-bundle reconstruction was also analysed to evaluate its effect to reduce GBA. A repeated-measures ANOVA was used to compare GBA difference at three flexion angles, by three techniques or of three bundles.

RESULTS

GBA changed substantially with knee motion, and it was highest at full extension (p < 0.001) in each surgical technique. OI technique exhibited highest GBA for anteromedial bundle (94.3° ± 5.2°) at extension, followed by TP (83.1° ± 6.5°) and TT (70.0° ± 5.2°) techniques (p < 0.01). GBA for posterolateral bundle at extension were also high in OI (84.6° ± 7.4°), TP (83.0° ± 6.3°) and TT (77.2° ± 7.0°) techniques (n.s.). Single-bundle grafts did not decrease GBA compared with double-bundle grafts. In OI technique, a more proximal location of the femoral exit reduced GBA of each bundle at extension and 90° flexion.

CONCLUSION

A significant GBA change with knee motion and considerably steep bending at full extension, especially with OI and TP techniques, were simulated. Although single-bundle technique did not reduce GBA as seen in double-bundle technique, proximal location of femoral exits by OI technique, with tunnels kept in anatomic position, was effective in decreasing GBA at knee extension and flexion. For clinical relevance, high stress on graft and bone interface has been suggested by steep GBA at full extension after anatomic ACL reconstruction.

LEVEL OF EVIDENCE

Therapeutic study (prospective comparative study), Level II.

Long-term rate of graft failure after ACL reconstruction: a geographic population cohort analysis

PURPOSE

Graft failure following anterior cruciate ligament reconstruction (ACLR) is a devastating injury among patients returning to activity. The goals of this study were to define the long-term rate of graft failure after ACLR in the general population and evaluate factors associated with graft failure.

METHODS

This long-term observational study included a population-based incidence cohort of patients who underwent primary ACLR after diagnosis with new-onset, isolated ACL tears between 1990 and 2010. For all patients, a chart review was performed to collect information related to the initial injury, treatment, and outcomes. Patients were retrospectively followed to determine the incidence of graft failure following ACLR.

RESULTS

The study cohort consisted of 1355 patients with new-onset, isolated ACL tears treated with ACLR. At a mean follow-up of 10.0 years (±6.4 years) following ACLR, a total of 72 patients (5.3 %) sustained ipsilateral graft failure. The graft survival following ACLR was 99.7 % at 1 year, 96 % at 5 years, 94 % at 10 years, 93 % at 15 years, 92 % at 20 years and 91 % at 25 years. Among patients 22 years or younger (n = 571), the rate of graft failure was significantly higher compared to patients older than 22 years (6.3 vs. 4.6 %, p = 0.04). The rate of graft failure decreased significantly over the 21-year observation period of this study (p < 0.0001).

CONCLUSIONS

Among all patients receiving primary ACLR, graft failure remains an uncommon but functionally devastating outcome with an estimated graft survival rate of 91 % at 25 years following surgery. Patients aged 22 or younger had a significantly higher rate of graft failure than older patients. The rate of graft failure decreased over the 21-year span of this study.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Incidence of Anterior Cruciate Ligament Tears and Reconstruction: A 21-Year Population-Based Study

BACKGROUND

The incidence of isolated anterior cruciate ligament (ACL) tears in the general population is not well defined.

PURPOSE/HYPOTHESIS

The purpose of this study was to define the population-based incidence of ACL tears, describe trends in ACL injuries over time, and evaluate changes in the rate of surgical management. The hypothesis was that the incidence of ACL injury and the rate of subsequent ACL reconstruction increase over time.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

The study population included 1841 individuals who were diagnosed with new-onset, isolated ACL tears (without concomitant ligament injury that required surgery) between January 1, 1990, and December 31, 2010. The complete medical records were reviewed to confirm diagnosis and to extract injury and treatment details. Age- and sex-specific incidence rates were calculated and adjusted to the 2010 US population. Poisson regression analyses were performed to examine incidence trends by age, sex, and calendar period.

RESULTS

The overall age- and sex-adjusted annual incidence of ACL tears was 68.6 per 100,000 person-years. Incidence was significantly higher in male patients than in females (81.7 vs 55.3 per 100,000, P < .001). The incidence of isolated ACL tears decreased significantly over time in males (P < .001) but remained relatively stable in females. Age-specific patterns differed in male and female patients, with a peak in incidence (241.0 per 100,000) between 19 and 25 years in males and a peak in incidence (227.6 per 100,000) between 14 and 18 years in females. The rate of ACL reconstruction increased significantly over time in all age groups (P < .001).

CONCLUSION

With an annual incidence of 68.6 per 100,000 person-years, isolated ACL tears remain a common orthopaedic injury. Differences in age-specific incidence trends in male and female patients may potentially reflect differences in sports participation patterns through the high school and college years. The significant increase in the rate of ACL reconstruction over time may reflect changing surgical indications or an increasing desire among patients to return to high levels of activity after ACL injury.

The Lateral Meniscus as a Guide to Anatomical Tibial Tunnel Placement During Anterior Cruciate Ligament Reconstruction

Purpose:

The aim of the study is to show, on an MRI scan, that the posterior border of the anterior horn of the lateral meniscus (AHLM) could guide tibial tunnel position in the sagittal plane and provide anatomical graft position.

Method:

One hundred MRI scans were analysed with normal cruciate ligaments and no evidence of meniscal injury. We measured the distance between the posterior border of the AHLM and the midpoint of the ACL by superimposing sagittal images.

Results:

The mean distance between the posterior border of the AHLM and the ACL midpoint was -0.1mm (i.e. 0.1mm posterior to the ACL midpoint). The range was 5mm to -4.6mm. The median value was 0.0mm. 95% confidence interval was from -0.5 to 0.3mm.

A normal, parametric distribution was observed and Intra- and inter-observer variability showed significant correlation (p<0.05) using Pearsons Correlation test (intra-observer) and Interclass correlation (inter-observer).

Conclusion:

Using the posterior border of the AHLM is a reproducible and anatomical marker for the midpoint of the ACL footprint in the majority of cases. It can be used intra-operatively as a guide for tibial tunnel insertion and graft placement allowing anatomical reconstruction. There will inevitably be some anatomical variation. Pre-operative MRI assessment of the relationship between AHLM and ACL footprint is advised to improve surgical planning.

Level of Evidence:

Level 4.

Femoral and tibial tunnel positioning on graft isometry in anterior cruciate ligament reconstruction: a cadaveric study

PURPOSE

To assess distance changes between the femoral and tibial attachment points of 3 different anterior cruciate ligament (ACL) tunnel entry positions throughout the range of knee motion in cadaveric knees.

METHODS

The ACLs of 11 fresh-frozen cadaveric knees (from 6 men and 5 women) were removed using radiofrequency. Three tibial tunnel placements were made using a cannulated awl, and three 2.4-mm pilot tunnels were drilled on the lateral femoral condyle. One end of an inelastic suture was inserted from each of the 3 femoral holes and fixed on the femoral cortex using a suture button in turn, whereas the other end of the suture was passed through the cannulated awl and fixed on each of the 3 tibial placements in turn, with constant tension. Distance changes of the suture throughout the range of knee movement (0º, 90º, and 135º of knee flexion) were measured for each combination of tibial and femoral positions.

RESULTS

The distance was minimum when the knee was in full extension (p < 0.0001). Most of the distance changes occurred during initial flexion (0º-90º). The most isometric position (mean ± standard deviation [SD] distance change, 2.78 ± 0.93 mm; p < 0.0001) was noted when the suture was at the anteromedial bundle placement in the femur and anterior in the tibia. The least isometric position (mean ± SD distance change, 10.37 ± 2.08 mm; p < 0.0001) was noted when the suture was at the mid-bundle position in the femur and at the posterolateral bundle insertion in the tibia. The anatomic position resulted in a mean ± SD distance change of 7.63 ± 2.01 mm (p < 0.0001). The femoral position had a greater influence on distance change than the tibial position.

CONCLUSION

None of the ACL graft positions was isometric. Anatomic ACL positioning resulted in comparable anisometry to the native ACL. The minimum distance for all graft positions was noted in full extension, in which position the graft should be fixed during anatomic ACL reconstruction.

Human knee laxity in ACL-deficient and physiological contralateral joints: intra-operative measurements using a navigation system

Background

The comprehension of human knee laxity and of the failures of relevant surgical reconstructions of the anterior cruciate ligament (ACL) can be enhanced by the knowledge of the laximetric status of the contralateral healthy knee (CHK). Rarely this is available in patients, directly from the skeletal structures, and for a number of the standard clinical tests. The general aim of this study was to measure the extent to which laxity occurs immediately before surgery in the ACL deficient knee (ADK) with respect to CHK, in a number of standard clinical evaluation tests.

Method

Thirty-two patients with ACL deficiency were analyzed at ADK and at CHK by a navigation system immediately before reconstructions. Knee laxity was assessed based on digitized anatomical references during the antero-posterior drawer, Lachman, internal-external rotation, varus-valgus, and pivot-shift tests. Antero-posterior laxity was normalized based on patient-specific length of the tibial plateau.

Results

In the drawer test, statistical significance (p < 0.05) was found for the larger antero-posterior laxity in ADK than in CHK, on average, of 54' in the medial and 47' in the lateral compartments, when measured in normalized translations. In the Lachman test, these were about 106' and 68'. The pivot-shift test revealed a significant 70' larger antero-posterior central laxity and a 32' larger rotational laxity. No statistically relevant differences were observed in the other tests.

Conclusion

The first conclusion is that it is important to measure also the antero-posterior and rotational laxity of the uninjured contralateral knee in assessing the laxity of the injured knee. A second is that the Lachman test shows knee laxity better than the AP drawer, and that the pivot-shift test was the only one able to reveal rotational instability. The present original measurements and analyses contribute to the knowledge of knee joint mechanics, with possible relevant applications in biomedical and clinical research.

Anatomic anterior cruciate ligament reconstruction using distally inserted doubled hamstrings tendons

Many surgical techniques aimed to obtain an anatomical anterior cruciate ligament reconstruction using the hamstrings tendons are described in the literature. All of these techniques encompass the detachment of the tibial insertion of the hamstrings tendons, thus damaging the neurovascular supply of the tendons and resulting in lower residual proprioceptivity and worse ligamentization of the graft. This article describes a new technique that permits an anatomic single-bundle ACL reconstruction using distally inserted doubled hamstrings tendons fixed at the femoral level with a second-generation cortical suspensory device.