Introduction : The purpose of the study is to compare in a randomised clinical double blind trial two methods of hamstring ACL reconstruction, the SIngle Bundle (SB) and the Double Bundle (DB).

Materials and methods: Seventy patients, with a chronic ACL insufficiency, were randomized to receive a unilateral single or double bundle ACL reconstruction. All the operations were performed by the same surgeon using the same two incision outside-in technique. The tibial guide wire was introduced with a 65 degrees Howell guide in extension to avoid impingment. To introduce the second tibial wire (posterolateral wire) a prototype guide that lets you place the wire with a fixed angulation and a fixed distance (9 mm) from the first was used. On the femoral side we used a modified Rear Entry guide. In a SB reconstruction the 10.00 o’clock position (right knee), intermediate between the two anatomic bundles, was used. In a DB reconstruction the first wire was placed in the anteromedial insertion area, close to the “over the top” position on the lateral wall and for the second wire the same prototype guide that gives you the correct angulation and distance with the first (10 mm) was used. The direction was chosen in order to exit 5 mm close to the posterior cartilage. The graft was prepared and pretensioned as to have two arms of the same diameter. It was fixed on the cortex of the tibia by means of a titanium ring bridge when doing a SB and looped around a cortical bony bridge when doing a DB. Tensioning and femoral fixation of the SB was done at 20 degrees, while in the DB tensioning and fixation of the PL bundle was achieved first after cycling at 10–15 degrees and of the AM bundle at 40–45 degrees. Femoral fixation was obtained via RCI titanium interference screws and one additional cortical titanium staple. The same moderately aggressive rehabilitation was utilized in both groups. Outcome assessment was performed by an indipendent observer, blinded to the involved leg and type of reconstruction, using the new IKDC form, the KOOS score, the KT-1000 arthrometer.

Results: All patients reached a minimum follow-up of one year. No difference was found in terms of overall KOOS and IKDC subjective scores. A significant difference was found (p< .001) in KT data and in IKDC final ojective scores (Excellent-A-result: 73% SB and 95% DB). he DB group showed a tred to less pivot shift (glide).

Conclusion: In the short period the DB reconstruction offered better knee stability and better objective results than the 10.00 o’clock SB. Longer follow up and accurate instrumented in vivo rotational stability assessment is probably needed to further disclose small but important differences.

Static finite-element (FE) analysis has been extensively used to examine polyethylene stresses in Total Knee Arthroplasty (TKA). The aim of this study was to use an explicit-dynamic FE approach with force driven models to simulate both the kinematics and the internal stresses within a single analysis of the Meniscal Bearing Knee (MBK, Zimmer, Warsaw, IN) prosthesis

The MBK is a mobile-bearing prosthesis (rotating and AP-gliding) with complete femorotibial conformity throughout motion owing to spherical femoral condyles. The FE meshes of the MBK were created from data obtained from the manufacturer as Initial Graphics Exchange Specification (IGES) files. Three-dimensional FE models of the original MBK design and of two modified versions (MBK-Flex and MBK-PS) were generated in Hypermesh 5.1 software. The tibial insert was modeled as a flexible body with 82212 noded solid tetrahedral elements (Poisson ratio: 0.46). The femoral and tibial components were modeled as rigid bodies. No abnormal alignment or soft tissue imbalance were assumed. Linear soft tissue constraints (30 N/mm AP and 0.6 N-m/degree rotational displacements) were included. Axial load was 4.9mm medially displaced to achieve amedially-biased (60–40) condylar load allocation. Waveforms to simulate gait, stair-climbing and deep-knee-bending with the FE models were obtained from the proposed International Standards Organization 14243–1 and from literature data.

Peak contact stresses for each activity evaluated were below 11 MPa for both the original and modified MBK versions. Kinematics analysis showed similar amount of displacements (average rotations: 3.7°: average AP-glide: 2.5mm) for the various design during gait. In simulated stair-climbing and deep-knee-bending the PS version showed a more reproducible pattern of posterior rollback in flexion without increasing contact stresses.

Explicit FE analysis is an efficient screening tool before in-vivo or in-vitro testing. It provides a means of testing the effect of variables such as change in prosthetic design, surgical techniques and applied loads on knee forces and kinematics.

Objective: To compare double bundle ACL reconstruction kinematics to single bundle reconstruction, intact knee and ACL deficient knee employing an electromagnetic device in six cadaver knees under different antero-posterior and rotational loading conditions.

Methods: All the tests were performed with an intact ACL, with a deficient ACL and after single and double bundle ACL reconstruction.

In double bundle ACL reconstruction two tibial tunnels were drilled: for the anteromedial the 65 degrees Howell guide was employed; the posterolaetral was drilled through a prototype jig attached to the first guide. Two femoral tunnels were drilled outside-in with the Rear Entry guide. A 6 millimetres bovine tendon graft was employed and fixed to bone with interference screws.

Results: Posterior drawer loading conditions did not show differences between intact knee, single and double ACL reconstruction independently from rotational stresses.

Under an anterior drawer test double bundle ACL reconstruction restored anteroposterior laxity significantly better than single bundle reconstruction at 20 and 40 degrees of flexion. A trend towards a better rotational control of double bundle reconstruction was observed in extension.

Thirty patients with chronic lesions of the ACL underwent reconstruction of the ACL with double bundle technique. A wire at 65° was used for AM tibial tunnel and a prototype was used for the PL. For femoral tunnels, a transtibial technique was applied in fifteen patients and the outside-in technique was used in fifteen more. All patients had an MRI after three months. The tunnels position was studied with Amis’ circle method, as a proportion of the circle’s height and width. We compared the proportion of the anatomical data on fourteen cadaveric knees. In the transtibial group the AM tunnel was at 56% of the circle’s height and at 65%of the depth (mean); the PL was at 40% of the circle’s height and 54% of the depth. In the out-side group the AM tunnel was 48%of the circle’s height and at 66% of the depth; the PL one was at 32%of the circle’s height and at 61%of the depth. In corpses the AM insertion was at 50% of the circle’s height and 69% of the depth (mean). In conclusion the outside-in technique allows better anatomical positioning.

Purpose: Prospectively compare 3 different techniques of ACL reconstruction with autologous hamstrings graft.

Material and methods: 3 comparable groups of 25 knees each were selected. An arthroscopic single incision reconstruction was performed in all groups. In group A, a single bundle graft was inserted. In group B a double bundle reconstruction was performed with 1 tibial and 2 femoral tunnels. In group C, 2 tibial and 2 femoral tunnels were drilled. Fixation was achieved in all knees with Endobutton CL proximally and Washerloc screw distally. Outcome assessment was performed at 4 and 12 months postoperatively by an independent observer, using new IKDC evaluation form, the KT-1000 arthrom-eter, and a radiographic investigation.

Results: At 12 months FU the subjective score was 81 in group A, 76 in group B, and 89 in group C. The final IKDC score was satisfactory (A+B) in over 90% of the patients. The KT-1000 anterior tibial translation was 2.3, 2.5 and 1.9 mm in group A, B, and C respectively. The radiographic study showed no differences between the 3 groups in terms of incidence of tunnel widening.

Conclusions: At a minimum FU of 1 year we could not show a statistically advantage of the two bundle compared to the single bundle.

The influence of Posterior Cruciate Ligament (PCL) removal and re-establishment of the posterior condylar recess on flexion and extension gaps width during posterior-stabilized Total Knee Arthroplasty (TKA) is still controversial. It has been reported that PCL resection lead to a selective increase of the flexion space of 3–4 mm, creating a potential for instability in flexion. Our hypothesis was that these surgical steps will equally increase both gaps. Measurements of the flexion and extension gaps heights were obtained during different surgical phases in 50 consecutive primary posterior-stabilised TKAs using a tensor device and a calibrated torque wrench. There was a slight symmetrical increase in both gaps after PCL release. In extension the width of the gap increased on average 1.3 mm and 1.0 mm in the medial and lateral compartment respectively. The same pattern was observed in flexion, averaging 1.3 mm medially and 1.3 mm laterally. Another increase of the two gaps was observed after the posterior condylar osteophytes were removed and the posterior recess was re-established. The gaps in extension increased, with respect to the baseline value, on average 1.8 mm medially and 1.8 mm laterally, while in flexion the increase averaged 2.0 mm and 2.2 respectively on the medial and lateral side. Again there were no statistical differences between flexion and extension gaps. No independent differences between the flexion and extension gaps were found in any considered surgical phase. PCL removal and re-establishment of posterior condylar recess does not seem to require any additional consideration in gap balancing during posterior-stabilized TKA.

Introduction: Static finite-element (FE) analysis has been extensively used to examine polyethylene stresses in Total Knee Arthroplasty (TKA). The aim of this study was to use an explicit-dynamic FE approach with force driven models to simulate both kinematics and internal stresses within a single analysis of the Meniscal Bearing Knee (MBK, Zimmer, Warsaw, IN).

Material and methods: The MBK is a mobile-bearing prosthesis (rotating and AP-gliding) with complete femoro-tibial conformity throughout motion owing to spherical femoral condyles. The FE meshes of the MBK were created from data obtained from the manufacturer as Initial Graphics Exchange Specification (IGES) files. Three-dimensional FE models of the original MBK design and of two modified versions (MBK-Flex and MBK-PS) were generated in Hypermesh 5.1 software. The tibial insert was modeled as a flexible body with 82212 noded solid tetrahedral elements (Poisson ratio: 0.46). The femoral and tibial components were modeled as rigid bodies. Linear soft tissue constraints (30 N/mm AP and 0.6 N-m/degree rotational displacements) were included. Axial load was 4.9mm medially displaced to achieve a medially-biased (60–40) condylar load allocation. Waveforms to simulate gait, stair-climbing and deep-knee-bending with the FE models were obtained from the proposed International Standards Organization 14243–1 and from literature data.

Results: Peak contact stresses for each activity evaluated were below 14 MPa for both the original and modified MBK versions. Kinematics analysis showed similar amount of displacements (average rotations: 3.7°: average AP-glide: 2.5mm) for the various design during gait. In simulated stair-climbing and deep-knee-bending the PS version showed a more reproducible pattern of posterior roll-back in flexion without increasing contact stresses.

Conclusion: Explicit FE analysis is an efficient screening tool before in-vivo or in-vitro testing. It allows to test the effects of variables such as change in prosthetic design, surgical techniques and loads on knee forces and kinematics.

Introduction: Inadequate control of postoperative pain after total knee arthroplasty (TKA) has been associated with a poor functional recovery. This study investigated whether the addition of a single injection femoral nerve block (FNB) to continuous epidural analgesia (EA) provides improved pain control, lowered side effects, and a further acceleration in achievement of rehabilitation goals.

Material and methods: Eighty patients undergoing TKA and receiving EA with 18 ml of 0.5% marcaine were randomized whether to receive or not a single dose of FNB. A nerve stimulator and 30 ml of 0.375% marcaine with 5 μg/ml of epinephrine were used to perform FNB prior to surgery. Post-operative continuous EA was self-administered by the patient adding bolus (up to 4bolus/hour) to the basal infusion rate of 2 ml/hour of 0.175% marcaine. Standardized post-operative rehabilitation protocol were followed for both groups. Therapists and clinicians were blinded to treatment group. Overall narcotic consumption, bolus dosing, and side effects were recorded. Outcomes measurements included postoperative strength and sensation, range of motion and progression, pain score (VAS), achievements of functional milestones and length of stay.

Results: Femoral nerve block group had significantly lower pain scores and lower epidural consumption in comparison to the group without block (p< 0.01). Range-of-motion was significantly greater through post-operative day three in the FNB group (p< 0.04). There was a consistent trend toward improved achievements in rehabilitation milestones after FNB. Decreased quadriceps strength was noted in 33% of the FNB patients on post-operative day one compared to 10% of the patients with isolated EA.

Discussion: We found significant improvements both in terms of analgesia and in functional parameters adding a FNB to continuous EA following TKA. Combination of the two techniques has a sound basis for preventing severe post-operative pain after TKA.

In the last few years the number of women who practise sport activities has substantially increased and this has led to an increase in the incidence of ACL tear in females. The aim of this study is to assess outcome differences at a minimum 3-year follow-up after ACL reconstruction in women using either a patellar tendon (BPTB) or a quadrupled-looped hamstring (DSTG) autograft fixed with modern devices.

Fifty women with a chronic, isolated ACL tear were randomised to receive a DSTG or BPTB graft for ACL reconstruction. Both groups were comparable as to age, injury-surgery, activity level, meniscal tears, surgical technique and reabilitation. All patients were prospectively evaluated by an independent observer using the IKDC form, the FKSAKP Score, the KT-1000 arthrometer and the Cybex NORM dynamometer. A radiographic study was performed to investigate tunnel widening.

All but two patients were satisfied with the reconstruction. The average side-to-side difference in anterior tibial translation was 2.4 mm in the BPTB group and 2.5 mm in the DSTG group. The final result was A (normal knee) in 56% and in 60% of the BPTB and the DSTG knees, respectively. A failure (4%) was present in each group. Muscle strength deficits at 60°/s, 120°/s and 180°/s were within 10% for extensors and within 5% for flex-ors in both groups. No statistically significant differences were found in terms of subjective satisfaction, objective evaluation, knee stability and muscle strength recovery. The BPTB group showed a higher incidence of postoperative kneeling discomfort (p< 0.05) and a larger area of decreased skin sensitivity (p< 0.001). The DSTG group showed a higher incidence of femoral tunnel widening (p=0.02).

Using strong and stiff fixation devices, ACL reconstruction in women is not influenced by the graft choice.