The concept of decellularised xenografts as a basis for anterior cruciate ligament (ACL) reconstruction was introduced to overcome limitations in alternative graft sources such as substantial remodelling delaying recovery and donor site morbidity. This study aimed to measure the biomechanical properties of decellularised porcine super flexor tendon (pSFT) processed to create ACL grafts of varying diameters, with a view to facilitating production of stratified ‘off the shelf’ products with specified functional properties for use in ACL reconstructive surgery. Decellularisation was carried out using a previously established procedure, including antibiotic washes, low concentration detergent (0.1% sodium dodecyl sulphate) washes and nuclease treatments. Decellularised pSFTs were prepared to create double-bundle grafts of 7, 8 and 9mm diameter (n=6 in each group). Femoral and tibial fixations were simulated utilising Arthrex suspension devices (Tightrope®) and interference screws in bovine bone respectively. Dynamic stiffness and creep were measured under cyclic loading between 50–250N for 1000 cycles at 1Hz. This was followed by ramp to failure at 200mm/min from which linear stiffness and load at failure were measured. Data were analysed using either 1- or 2-way ANOVA as appropriate with Tukey post-hoc analysis (p<0.05). Significant differences were found between all groups for dynamic stiffness and between 7 & 9mm and 8 & 9mm groups for dynamic creep. Significant differences were also found between 7, 8 & 9mm groups for linear stiffness (167.8±4.9, 186.9±16.6 & 216.3±12.4N/mm respectively), but no significant differences were found between groups for load at failure (531.5±58.9, 604.1±183.3 & 627.9±72.4N respectively). This study demonstrated that decellularised pSFTs possess comparable biomechanical properties to other ACL graft options (autografts and allografts). Furthermore, grafts can be stratified by their diameter to provide varying biomechanical profiles depending on the anatomy and individual needs of the recipient

Anterior cruciate ligament (acl) reconstruction is one of the most commonly performed procedures in orthopedics for acl injury. While literature suggest short-term good-to-excellent functional results, a significant number of long-term studies report unexplained early oa development, regardless type of reconstruction. The present study reports the feasibility analysis and development of a clinical protocol, integrating different methodologies, able to determine which acl reconstruction technique could have the best chance to prevent oa. It gives also clinicians an effective tool to minimize the incidence of early oa. A prospective clinical trial was defined to evaluate clinical outcome, biochemical changes in cartilage, biomechanical parameters and possible development of oa. The most common reconstruction techniques were selected for this study, including hamstring single-bundle, single-bundle with extraarticular tenodesis and anatomical double-bundle. Power analysis was performed in terms of changes at cartilage level measurable by mri with t2 mapping. A sample size of 42 patients with isolated traumatic acl injury were therefore identified, considering a possible 10% to follow-up. Subjects presenting skeletal immaturity, degenerative tear of acl, other potential risk factors of oa and previous knee surgery were excluded. Included patients were randomized and underwent one of the 3 specified reconstruction techniques. The patients were evaluated pre-operatively, intra-operatively and post-operatively at 4 and 18 months of follow-up. Clinical evaluation were performed at each time using subjective scores (koos) and generic health status (sf-12). The activity level were documented (marx) as well as objective function (ikdc). Preliminary results allow to verify kinematic patterns during active tasks, including level walking, stair descending and squatting using dynamic roentgen sterephotogrammetric analysis (rsa) methodology before and after the injured ligament reconstruction. Intra-operative kinematics was also available by using a dedicated navigation system, thus to verify knee laxity at the time of surgery. Additionally, non-invasive assessment was possible both before the reconstruction and during the whole follow-up period by using inertial sensors. Integrating 3d models with kinematic data, estimation of contact areas of stress patterns on cartilage was also possible. The presented integrate protocol allowed to acquired different types of information concerning clinical assessment, biochemical changes in cartilage and biomechanical parameters to identify which acl reconstruction could present the most chondroprotective behavior. Preliminary data showed all the potential of the proposed workflow. The study is on-going and final results will be shortly provided

We evaluated two reconstruction techniques for a simulated posterolateral corner injury on ten pairs of cadaver knees. Specimens were mounted at 30° and 90° of knee flexion to record external rotation and varus movement. Instability was created by transversely sectioning the lateral collateral ligament at its midpoint and the popliteus tendon was released at the lateral femoral condyle. The left knee was randomly assigned for reconstruction using either a combined or fibula-based treatment with the right knee receiving the other. After sectioning, laxity increased in all the specimens. Each technique restored external rotatory and varus stability at both flexion angles to levels similar to the intact condition. For the fibula-based reconstruction method, varus laxity at 30° of knee flexion did not differ from the intact state, but was significantly less than after the combined method.

Both the fibula-based and combined posterolateral reconstruction techniques are equally effective in restoring stability following the simulated injury.

The purpose of this anatomical study was to explore the morphological variations of the semitendinosus and gracilis tendons in length and cross-section and the statistical relationship between length, cross-section, and body height.

We studied the legs of 93 humans in 136 cadavers. In 43 specimens (46.2%) it was possible to harvest the tendons from both legs.

We found considerable differences in the length and cross-section of the semitendinosus and the gracilis tendons with a significant correlation between the two. A correlation between the length of the femur, reflecting height, and the length of the tendons was only observed in specimens harvested from women. The reason for this gender difference was unclear. Additionally, there was a correlation between the cross-sectional area of the tendons and the length of the femur. Surgeons should be aware of the possibility of encountering insufficient length of tendon when undertaking reconstructive surgery as a result of anatomical variations between patients.