Alpha Lipoic Acid (L.A.) is an effective natural antioxidant discovered in the human body in 1951 from L.J. Reed and I.C. Gunslaus from liver.

It is inside broccoli, spinach and red meats, especially liver and spleen.

Actually it is largely used as antioxidant in antiaging products according to the low toxicity level of the product.

The present study take into consideration the possibility to reduce oxidation of medical irradiated UHMWPE GUR 1050, mixing together polyethylene powder and Alpha Lipoic Acid powder.

The study is composed of two parts.

Part 1 Thermostability of alpha lipoic acid during polyethylene fusion Part 2 detection of oxygen level in artificially aged irradiated polyethylene

Solid pieces were made with Gur 1050 powder (Ticona Inc., Bayport, Tex, USA) and mixed with Alpha Lipoic Acid (Talamonti, Italy, Stock 1050919074) 0,1%-­‐0,3%-­‐0,5%-­‐1%-­‐2% and gamma ray irradiated with 30 kGy (Isomedix, Northborough, MA).

An owen (80° Celsius) was used to produce an aging effect for 35 days in the doped and control samples (Conventional not doped polyethylene). This process simulate an aging effect of 10 years into the human body.

Part 1 : THERMAL STABILITY : a Fourier Transfer Infra Red (FTIR) test was made in pieces molded in a cell at 150° and 200°Celsius and pressure of 200 MPa comparing to the UHMWPE powder mixed with alpha lipoic acid. The presence of Alpha Lipoic Acid in the polyethylene was found at any depth in the manufacts.

Part 2 : OXIDATION OF THE SURFACE : After 5 weeks at 80° Celsius in a owen (ASTM standard F-­‐2003-­‐02)A FOURIER TRANSFER INFRA RED TEST (FTIR) was made in the superficial layer and deeper on the undersurface of doped 0,1% and conventional UHMWPE.

The antioxidation limit is defined as the ratio of the area under 1740cm/−­‐1 carbonyl and 1370 cm/−­‐1 Methylene absorbance peaks.

In conventional UHMWPE oxidation is detected on the surface and decreases in the deeper layers down to zero under 1500 Micron.

In the doped UHMWPE, FTIR demonstrate a very low oxidation limit on the surface and at any depth, comparing to conventional UHMWPE.

The examples show that Lipoic Acid is effective as antioxidant in irradiated UHMWPE and it is stable with respect to thermal treatment.

For any figures or tables, please contact authors directly.

Femoral neck fractures are the second cause of hospitalization in elderly patients. Nowadays it is still not clear whether surgical treatment may provide better clinical outcome than conservative treatment in patients affected by mental disorders, such as senile dementia.

The aim of this study was to retrospectively assess mortality and clinical and functional outcome after hemi arthroplasty operation following intracapsular neck fractures in patients with senile dementia.

Between 2008 and 2014, 819 patients were treated at our Orthopaedic Institute for neck fracture of the femur (mean age: 83.8 years old). Eighty-four of these showed clear signs of cognitive impairment at time of admission in the Emergency Department. Mental state of patients was assessed in all cases, as routine, at the Emergency Room with the Short Portable Mental Status Questionnaire (Sh-MMT) and the Mini Mental State Examination (MMSE).

Patients were divided in two groups depending whether they were surgically treated with hemiarthroplasty (Group B, 46 patients; 35 females, 11 males; mean age: 88.5 y.o.) or conservatively treated (Group C, 38 patients; 28 females, 10 males; mean age: 79.5 y.o.).

These two groups were compared with a matched case-control group of patients surgically treated with no mental disorders (Group A, 40 patients; 34 females, 6 males; mean age: 81.5 y.o.)

Incidence of mortality, systemic or local complications and functional clinical outcomes were evaluated with the ADL score and the Barthel index.

Mortality rate was 35% (14 patients) for Group A, 50% (21 patients) for Group B and 95% (22 patients) for Group C. Paired t-test, with significance rate set at 0.05, showed significant higher mortality rate in Group A compared to both Group B (p:0.02) and Group C (p:0.001), and also between Group B and Group C (p:0.01). Three orthopaedic complications were found in Group B (two cases of infection and one dislocation of the prosthesis) while none in Group A (p<0.001). There have been 14 overall general complication in Group A (33%), 16 in group B (38%) and 15 in Group C (65%), with significant higher rate in Group B vs. Group A (p:0.02) and in group C vs. Group B (p: 0.001)

Activity daily living scale and Barthel Index results showed higher results in Group B than Group C both in terms of recovery of walking ability and daily living (hairdressing, wearing clothes, eating).

For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Background

Limb length discrepancy after total hip replacement is one of the possible complications of suboptimal positioning of the implant and cause of patients dissatisfaction.

Computer assisted navigation become affirmed in last years for total hip replacement surgery and it is also used for the evaluation of the intra-operative limb length discrepancy.

The purpose of this study is to verify the reliability of a navigation system with a dedicated software in intraoperative evaluation of limb lengthening and offset as compared with manual technique.

Introduction

The aim of this study is to investigate the accuracy and reliability of a Magnetic Resonance Imaging (MRI) based Patient Match Technology (PMT) system (VISIONAIRE, Smith & Nephew, Inc, Memphis, Tenn) by intraoperative use of VectorVision knee navigation software from BrainLAB (Redwood City, California, USA).

Introduction

In total knee arthroplasty extramedullary tibial guides could not to be as accurate as requested in obtaining proper alignment perpendicular to the mechanical axis. The aim of this study was to determine the accuracy of an accelerometer-based system (KneeAlign 2; OrthAlign Inc, Aliso Viejo, California) as evaluated by post-op X-rays analysis.

Alpha Lipoic Acid (L.A.) is an effective natural antioxidant discovered in the human body in 1951 from L.J. Reed and I.C. Gunslaus from liver. It is inside broccoli, spinach and red meats, especially liver and spleen. Actually it is largely used as antioxidant in antiaging products according to the low toxicity level of the product.

The present study take into consideration the possibility to reduce oxidation of medical irradiated UHMWPE GUR 1050, mixing together polyethylene powder and Alpha Lipoic Acid powder.

The study is composed of two parts.

Part 1 Thermostability of alpha lipoic acid during polyethylene fusion

Part 2 detection of oxygen level in artificially aged irradiated polyethylene

Solid pieces were made with Gur 1050 powder (Ticona Inc., Bayport, Tex, USA) and mixed with Alpha Lipoic Acid (Talamonti, Italy, Stock 1050919074) 0, 1% and gamma ray irradiated with 30 kGy (Isomedix, Northborough, MA).

An oven (80° Celsius) was used to produce an aging effect for 35 days in the doped and control samples (Conventional not doped polyethylene). This process simulate an aging effect of 10 years into the human body.

THERMAL STABILITY: a Fourier Transfer Infra Red (FTIR) test was made in pieces molded in a cell at 150° and 200°Celsius and pressure of 200 MPa comparing to the UHMWPE powder mixed with alpha lipoic acid. The presence of Alpha Lipoic Acid in the polyethylene was found at any depth in the manufacts.

figure 1: A Pure Lipoic Acid. B Lipoic Acid + UHMWPE melted 150° C. Lipoic Acid + UHMWPE melted 200° C° (A And B spectra subtracted UHMWPE)

OXIDATION: After 5 weeks at 80° Celsius in a oven (ASTM standard F-2003-02)A FOURIER TRANSFER INFRA RED TEST (FTIR) was made in the superficial layer and deeper on the undersurface of doped 0.1% and conventional UHMWPE.

The antioxidation limit is defined as the ratio of the area under 1740 cm/−1 carbonyl and 1370 cm/−1 Methylene absorbance peaks.

In conventional UHMWPE oxidation is detected on the surface and decreases in the deeper layers down to zero under 1500 Micron Fig 2.

figure 2 Pure polyethylene: A Surface, B 1500 Micron, C 3000 Micron

In the doped UHMWPE, FTIR demonstrate a very low oxidation limit on the surface and at any depth, comparing to conventional UHMWPE Fig 3.

figure 3 Doped UHMWPE A surface, B 700 micron deept, C 1700 micron deept

The examples show that Lipoic Acid is effective as antioxidant in irradiated UHMWPE and it is stable with respect to thermal treatment.

Manual postoperative CT calculation of anteversion and inclination of the acetabular cup can be inaccurate and depends on the observer's experience. The aim of this study is to describe and present a validation of a new CT-image-based dedicate software (EGIT) for calculation of the acetabular component placement.

The software principle is based on a three-dimensional reconstruction of a patient's bones from anatomical data collected postoperatively on the patient's CT scan.

15 Patient to be operated for THR were enrolled in this study. All patients were evaluated with post operative CT-scan. Measurement of Cup positioning were performed with two different methods: a manual method, performed by an expert radiologist, and a software CT image based method. Statistical analysis was performed with Intraclass Correlation Coefficent to asses interobserver and intraobserver reliability. A paired T-test was used to detect differences between manual and software methods.

The Intraclass Correlation Coefficient was excellent for both the intraobserver and interobserver reliability. As expected the ICC is higher in the interobserver case.

A mean cup anteversion of 14.2 (S.D. ±6.9), mean inclination of 44.2 (S.D.± 5.8) are detected with EGIT by the expert surgeon; Mean Cup anteversion of 13.6 (S.D. ± 5.11), mean inclination of 43.3 (S.D.± 5.1) are detected with manual method by expert radiologist. No statistical difference have been found (P> 0.05).

The EGIT software seems to be an easy, accurate and reproducible method to calculate acetabular cup positioning using standard post-operative CT scan in THA.

The choice of surgical technique for total hip arthroplasty (THA) can affect time and postoperative rehabilitation procedures. The aim of this prospective blinded cohort study is to determine significant differences in gait parameters in the short term between those patients who have experienced THA using a limited incision anterolateral intermuscular (MIS) approach compared with those who have experienced traditional lateral transmuscular (LTM) approach.

Thirty patients were enrolled in this study, 15 of who received the MIS technique and 15 the LTM approach. A single surgeon performed all the operations using short hip stem implants with 36mm femoral head size and all patients received a standard postoperative rehabilitation protocol. Patients, physiotherapists, and assessors were blinded to the incision used. Gait analysis was performed 30 day after surgery, when patients were able to ambulate without crutches.

Minimal differences in temporostatial parameters were shown between the MIS and LTM groups, whereas significant differences (p< 0.05) in kinematics (hip range of motion in sagittal, frontal and transverse planes), kinetics (hip flexion/extension and abduction/adduction moments) and electromiography parameters (gluteus medius activation pattern and degree of activity) between two groups.

This study demonstrates functional benefits of the minimally invasive incision over the standard lateral transmuscular approach in terms of walking ability 30 days postoperatively.

Introduction: Mechanical factors are thought to be one of the main reasons in determining tunnel enlargement after ACL reconstruction with hamstrings. The purpose of this prospective study was to evaluate how the different techniques may affect the bone tunnel enlargement.

Material and Method: Forty-five consecutive patients undergoing ACL reconstruction with the use of autologous doubled semitendinosus and gracilis tendons entered this study. They were randomly assigned to enter group A (In-Out technique, with cortical fixation and Interference screw) and group B (Out-In technique, metal cortical fixation on the femour and tibia). At a mean follow-up of 10 months, all the patients underwent clinical evaluation and a CT scan exam to evaluate the post-operative diameters of both femoral and tibial tunnels.

Results: The mean femoral tunnel diameter increased significantly from 9.05±0.3 mm (post op) to 10.01±2.3 mm (follow-up) in group A and from 9.04±0.8 mm to 9.3±1,12 mm in group B. The mean tibial tunnel diameter increased significantly from 9.03±0.04 mm to 10,68±2.5 mm in group A and from 9.04±0.03 mm to 10.±0,78 mm in group B. The mean increase in both femoral and tunnel diameters observed in group A was significantly higher than that observed in group B (p< 0.05). Stability evaluated with kt 1000 don’t significantly differ in the two groups

Conclusion: The results of this study suggest that different angular orientation techniques and different hardware devices may affect tunnel enlargement after hamstrings reconstruction. The reason can be reached from the different stiffness of the devices and their backlashes on the tunnels walls.

Septic arthritis after arthroscopic anterior cruciate ligament (ACL) reconstruction is a rare complication. In the literature, several different managements have been proposed.

A total of 1232 ACL reconstruction procedures were performed from January 2001 and December 2008. Twelve patients (0.97%) had a post-operative infection. The average age at trauma was 24 years (range:16–43). Treatment included continuous irrigation of the knee (4 hour/day for 2 days) and parenteral and oral antibiotics subsequently for a mean of 7 weeks (range:4–12 weeks). The average time at follow-up was 38 months (range 6–54 months). Follow-up included International Knee Documentation Committee (IKDC) forms, radiographs, the Tegner and Lysholm scores and KT-1000 arthrometric evaluation.

In all cases treatment of infection was successful. In no cases graft or hardware removal was needed. At final examination pivot shift was negative in 10/12 patients and 1+ in 2/12 patients. In all cases the Lachman was negative. The mean postoperative Tegner score was 7.2 (range 5–9), the mean Lysholm score was 98.3 (range 69–100). 10/12 patients were graded as Group A and 2/12 patients as group B using the IKDC. The mean postoperative manual maximum KT-1000 side to side difference was 2.3 (range1–4), with 10 patients between 0 and 3 mm and 2 between 3 and 5 mm. No significative bone tunnel enlargement was found.

The described treatment gives reliable results. There were no recurrences of septic arthritis or bone infection. No further surgeries were required. The graft can be retained during treatment of septic arthritis after ACL reconstruction.

The KT1000 is widely accepted as a tool for the instrumented measurement of the anteroposterior tibial translation. The aim of this study is to compare the data obtained with the KT1000 in ACL deficient knees with the data obtained using a navigation system during “in vivo” ACL reconstruction procedures and to validate the accuracy of the KT1000.

An ACL reconstruction was performed using computer aided surgical navigation (Orthopilot, B-Braun, A esculap, Tuttlingen, Germany) in thirty patients. Antero-posterior laxity measurements were obtained for all patients using KT1000 arthrometer (in a conscious state and under general anesthesia) and during surgery using the navigation system, always at 30° of knee flexion.

The mean AP translation was 14±4 mm and 15,6±3,8 using the KT1000 in conscious and under general anesthesia respectively (p=0.02) and 16,1±3,7 mm using navigation. Measurements with the KT1000 under general anesthesia were not different to those obtained “in vivo” with the navigation system (p=0,37).

In conclusion this study validates the accuracy of the KT1000 to exactly calculate AP translation of the tibia, in comparison with the more accurate measurements obtained using a navigation system.

Introduction: In the last few years minimally invasive surgery in hip replacement is becoming more popular among orthopaedic surgeons because of less morbidity and faster rehabilitation. However several complications have been reported expecially in the so called “learning curve” (first twenty cases). The purpose of this study is to evaluate the learning curve of three different minimally invasive approaches.

Methods and Materials: In this study three different surgical approaches of THA were evaluated: lateral mini incision (GroupA), minimally invasive anterior approach (GroupB) and minimally invasive antero lateral approach (GroupC). The first twenty cases of each surgical approach were selected and compared with a control group (GroupD) of 149 total hip replacement operated using a lateral standard approach (> 12 cm) in the same period by the same experienced surgeon.

In all cases a specialized dedicated surgical instrumentation was used. Inclusion criteria to enter the study group (A-B-C Groups) were:BMI< 30, diagnosis of primary osteoarthritis, age< 75 years.

Following parameters were evaluated: intra and post operative complications, total blood loss, time of surgery, component placement, length of hospital stay and functional outcomes (HHS, WOMAC) at six weeks.

Results: No dislocations, infections and early aseptic loosening were detected in groups A, B and C. No significant differences were detected regarding the length of hospital stay in all groups. In group B the time of surgery was significantly higher than in group D. The total blood loss of group A, B and C was statistically lower than group D. Clinical outcomes at six weeks in groups B and C were significantly better that in group A and D. The following complications were detected:

Group A: two sciatic nerve palsy (one transient and one permanent), one greater trochanter fracture, one femoral stem malposition.

Group B: one greater trochanter fracture, one proximal femoral fracture, one rupture of tensor fasciae latae, two haematomas.

Group C: no complications were detected.

In control group D (149 patients) the following complications were observed: one proximal femoral fracture, one case of cup malposition and one infection.

Conclusions: The main advantages of all MIS approaches seem to be the reduced total blood loss, even in the learning curve. However during learning curve the minimally invasive approaches seem to have a higher rate of complications than the standard procedures even in selected patients. In muscle sparing approaches (anterior and antero lateral) the early functional outcomes are better than other approaches (standard and mini incision). Among the evaluated minimally invasive procedures, the antero lateral approach seems to be safer and less demanding than others.

Cadeveric studies showed that single bundle ACL reconstructions were successful in limiting anterior tibial translation but were insufficient to control a combined rotatory load of internal and valgus torque. One possible cause of these condition could be that current single bundle procedures cannot realistically reproduce the complex anatomy of the ACL, especially the different function of its anteromedial(AM)and posterolateral(PL)bundle. The hypothesis of our study is that the addition of the PL bundle to the AM bundle, in an “in vivo” double bundle computer assisted ACL reconstruction, is actually able to reduce the internal rotation of the tibia at 30° degrees of knee flexion. Computer assisted ACL reconstruction has been used because it could be very effective in evaluating the global performance of the reconstructed knee.

Ten consecutive doble bundle ACL reconstructions were performed in our Hospital using hamstrings graft and the 2.0OrthoPilot-B. Braun-Aesculap ACLnavigation system. The average age of patients was 27.8 years.

The double-looped semitendinosus tendon replicating the AM bundle was fixed first at 60° of knee flexion. Than the gracilis tendon replicating the PL bundle was fixed at 15° of knee flexion. Maximum manual A–P displacement at 30° of flexion, maximum internal and external rotation of the knee were evaluated using the navigation system before surgery and after single(A–M)and double (AM+PL)bundle reconstruction. Statystical anlisys was done using paired T-test.

Before ACL reconstruction mean manual maximum AP displacement was 17.2mm;mean manual maximum internal rotation was 19.8mm and mean manual maximum external rotation was 16.8mm. After AM bundle reconstruction mean manual maximum AP displacement was 6.1mm;mean manual maximum internal rotation was 17.0mm and mean manual maximum external rotation was 16.3mm. After AM+PL bundles reconstruction mean manual maximum AP displacement was 5.3mm;mean manual maximum internal rotation was 16.2mm and mean manual maximum external rotation was 14.6mm. There was no statistically significant difference in the tibial internal rotation at 30° after single bundle(AM)and double bundle(AM+PL)reconstruction.

In this study the effectiveness of the PL bundle in controlling the internal rotation of the tibia, responsible of rotational instability of the knee, was evaluated in “in vivo” ACL reconstruction. The navigator system allowed us to obtain “in vivo” the real and correct value of AP displacement and internal and external rotation of the tibia before and after reconstruction.

Our hypothesis that the addition of the PL bundle to the AM bundle is actually able to reduce the internal rotation of the tibia at 30° degrees of knee flexion, minimizing the pivot shift phenomenon, on the basis of our study has not been confirmed.

The purpose of this paper is to investigate the relative contribution of each component in the ultimate strength and stiffness of the Evolgate (Citieffe), which is presently a widely used fixation device in DGST ACL reconstruction. The three components of the Evolgate were tested using fresh frozen animal tissue stored at −20° Celsius. Common extensor tendons were harvested from 20-month-old bovine forelimbs. Twenty-four tests were performed for each of the following configurations: six tests using Evolgate complete, six tests using screw alone, six tests using screw and washer and six tests using screw and coil. A randomised t-test was used; differences were considered significant when p< 0.05. The mean strength was: Evolgate complete 1314±194N; coil and screw 700±152N; screw alone 408±86N; and screw and washer 333±93N. There was a significant difference between fixation strength of Evolgate and the other devices, none between screw alone and screw and washer. The mean slippage of the Evolgate was significantly lower than the other devices. The mean stiffness of the Evolgate (269±14 N/mm) was significantly greater than the other devices. On the basis of the results of the present study, the coil appears to be the most important component of the Evolgate, resulting in a significant increase of the fixation strength of the screw. However, it is important to note that, as the washer alone does not improve the strength of the screw, if a washer is associated with a coil a further significant increase in strength and stiffness of the device is observed.

The surgical treatment of typical pathological conditions of the knee combined with deflections along the sagittal axis is complex, especially when the angles of such deflections are considerable in size.

Prior to treatment, the first problem concerns detecting the origin of the deflection, whether it is osseous, ligamentous or mixed, especially in cases of knee recurvation. The possibility of finding patients with what is known as “prophylactic” correction of the deflection is very rare.

Orthopaedic surgeons may encounter some cases in which deformation along the sagittal axis represents the primum movens of the pathology and others in which this deflection represents a further problem in curing the condition. The different situations may require the following different treatments: (a) Correction of the deflection; (b) correction of the deflection and the pathological condition; and (c) correction of the pathological condition and not the deflection.

We believe that, in the most serious cases, the deflection must be corrected and then meticulous pre-operative preparation is required. However, in order to select the most appropriate treatment, it is essential, in our opinion, to determine the cause of the deflection along the sagittal axis.

In our experience, the treatment of pathological conditions of the knee such as ligamentous reconstruction, knee arthroplasty and corrective osteotomies combined with deflection along the sagittal axis increase the difficulties of surgery, especially in cases of relevant knee recurvation, both osseous and ligamentous.

The biomechanical objective in total knee prostheses with mobile bearings was, and still is, to reduce UHMWPE wear and fracture. This does not mean that such prostheses do not produce polyethylene debris.

In our clinical experience we have used several types of prosthesis, in which over time, plastic materials have become diversified and various methods of sterilisation have been used, the prostheses becoming more and more sophisticated.

In our work we present the results of using a posterior cruciate ligament-retaining prosthesis with two mobile bearings (follow up 7–14 years), a posterior cruciate ligament-sacrificing prosthesis with a rotating platform (follow up 10 years to today) and a posterior cruciate ligament-retaining prosthesis with a rear-front translation platform (follow up 7 years to today).

Data on fractures and dislocation are only presented for the posterior cruciate ligament-retaining prosthesis with two mobile bearings. In no other cases were fractures or dislocation observed, except for one patient who had a dislocation after suffering a rotational tendon tear.

Our results show that larger surfaces tolerate the prosthesis stress better, although the type of polyethylene (with or without stearate, more or less crosslinked, sterilisation with or without air, sterilisation by high energy radiation or using gamma radiation, etc.) can influences debris production.

The purpose of our study was to determine the effect of 4 weeks and 12 weeks of implantation on the strength of a tendon graft in a bone tunnel using a low-profile fixation device, Evolgate, in an extra-articular ovine model. Moreover, we evaluated the histological changes.

The common digital extensor tendon was detached from the lateral femoral condyle and fixed with the Evolgate device in a 30-mm-long tunnel placed obliquely across the dense metaphyseal bone of the proximal tibia. We performed either biomechanical or histological study. Three sheep were sacrified at time 0 and their posterior limbs were used for biomechanical tests. Six sheep were used for biomechanical tests at time 1 (4 weeks) and at time 2 (12 weeks). The other three sheep were used for histological evaluation after 4 and 12 weeks of implantation. The biomechanical tests included a 50 N preload applied for 10 s and a cyclic load test in 50-N increments until failure to evaluate the ultimate failure load. We used a paired t-test to evaluate the difference between group at T1 and group at T2 with the control group at time 0, respectively. Tests were performed using an electromechanic machine (Zwick-Roell Z010, Zwick-Roell, Ulm, Germany). Data were recorded with dedicated software (Textexpert 8.1, Zwick-Roell).

The biomechanical results show an improvement of about 50% in strength after 4 and 12 weeks post-implantation, respectively. The histological evaluation shows a layer of cellular, fibrous tissue between the tendon and the bone, along the length of the bone tunnel; this layer progressively matured and reorganised during the healing process. The collagen fibres that attached the tendon to the bone resembled Sharpey fibres.

The strength of the interface was noted to have significantly and progressively increased between the second and the 12th week after the transplantation. The progressive increase in strength was correlated with the degree of bone ingrowth, mineralisation, and maturation of the healing tissue, noted histologically.

The purpose of this study is to biomechanically compare Evolgate and Intrafix using cyclic loading with final pull-out tests. Five pairs of double looped bovine digital extensor tendons and 10 porcine tibias were used. We evaluated the displacement at 1, 10, 100, 250, 500, 1000 and 1500 cycles. We used cyclic tests (1500 cycles between 50 and 200 N with final pull-out). Biomechanical tests were performed with use of a Zwick-Roell Z010 mechanical testing machine (Zwick-Roell, Germany), and the testing data were recorded with the accompanying software package (Testexpert 8.1, Zwick-Roell). A paired t-test was performed for statistical evaluation. There was no statistically significant difference in slippage between the two devices. The mean ultimate failure load at pull-out after 1500 cycles was 832±156 N for Intrafix and 1058±130 N for the Evolgate.The mean stiffness at pull-out was 269±86 for Intrafix and 247±44 for the Evolgate, and there were no statistically significant differences (p> 0.05). At statistical evaluation there was a difference in ultimate failure load between the IF and the EV (p< 0.05). Although further studies are needed to investigate bone growth into the tibia tunnel, Evolgate seems to be a good choice for tibial fixation of hamstring tendons. Moreover, Evolgate has higher values of strength than Intrafix.

Secure tendon-to-bone fixation is essential for successful rotator cuff repair. Thus, the biomechanical properties of devices used in rotator cuff repair should be better understood. This controlled laboratory study was performed to evaluate response to incremental cyclic loading of six different anchor-wire complexes commonly used in rotator cuff repair.

Two absorbable anchors 5 and 6.5 mm in diameter and one metallic anchor, coupled with both ethibond or fibrewire (FW) were tested on five pairs of fresh-frozen human cadaveric shoulders. An incremental cyclic load was applied until failure using a Zwich-Roell Z010 electromechanical testing machine. The ultimate failure load and mode of failure were recorded. A t-test was used for statistical analysis.

The FW suture coupled both with absorbable and metallic anchors provides a statistically significant stronger fixation. However, while the metallic anchors in most cases fail due to the slippage of the anchor, absorbable anchors fail due to rupture of the loop. The FW seems to increase the strength of fixation devices under cyclic load both using absorbable or metallic anchors with relevant differences in failure mode (slippage of the metallic anchor and loop failure in absorbable ones). Using a FW suture, the risk of metallic anchor migration might increase.