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Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_2 | Pages 19 - 19
1 Jan 2019
Mengoni M
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Ligaments and tendons are connective tissues with a highly hierarchical structure, from collagen fibres, to fibrils and fascicules. Their intricate structural arrangement produces an anisotropic non-linear elastic mechanical behaviour and a complex damage pattern before failure. Recent constitutive models have been developed with all parameters describing the structure of the tissue, with the advantage that they can in theory be measured on the tissue rather than being phenomenologically-derived. This is an ideal framework to model damage as its onset and propagation can be associated to changes in the structure directly. In this preliminary study, the possibility to identify damage mechanisms in the tissue structure using in silico models was analysed for both the anterior cruciate ligament, with fascicules forming a helix with its longitudinal axis, and the patellar tendon, with fascicules co-aligned with its longitudinal axis. Tissues of interest were modelled as cylinders submitted to uniaxial tension. Damage was modelled as either a reduction of collagen volume fraction with increased strain, assuming the number of collagen fibres sustaining load decreases as fibres fail, or a reduction of the modulus of the fibres, assuming pre-failure damage of the fibres. Each damage mechanism was associated with a damage variable with different fibre stretch threshold for damage initiation and assuming linear variation of damage until an arbitrary failure point. The apparent behaviour of the modelled tissues was significantly different as damage thresholds, damage mechanisms, type of fascicules were varied. This preliminary work showed that using a structural constitutive model to describe occurrence and propagation of structural damage in an in silico model of hierarchical connective tissues is a framework that can clearly differentiate at a macroscopic level between different values of damage threshold and different damage mechanisms for tissue with co-aligned or helical fascicules


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_5 | Pages 65 - 65
1 Apr 2019
DesJardins J Stokes M Pietrykowski L Gambon T Greene B Bales C
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Introduction. There are over ½ million total knee replacement (TKR) procedures performed each year in the United States and is projected to increase to over 3.48 million by 2030. Concurrent with the increase in TKR procedures is a trend of younger patients receiving knee implants (under the age of 65). These younger patients are known to have a 5% lower implant survival rate at 8 years post-op compared to older patients (65+ years), and they are also known to live more active lifestyles that place higher demands on the durability and functional performance of the TKR device. Conventional TKR designs increase articular conformity to increase stability, but these articular constraints decrease patient range of knee motion, often limiting key measures of femoral rollback, A/P motion, and deep knee flexion. Without this articular constraint however, many patients report TKR “instability” during activities such as walking and stair descent, which can significantly impede confidence of movement. Therefore, there is a need for a TKR system that can offer enhanced stability while also maintaining active ranges of motion. Materials and Methods. A novel knee arthroplasty system has been designed that uses synthetic ligament systems that can be surgically replaced, to provide ligamentous stability and natural motion to increase the functional performance of the implant. A computational anatomical model (AnyBody) was developed that incorporated ligaments into an existing Journey II TKR. Ligaments were modeled and given biomechanical properties from literature. Simulated A/P drawer tests and knee flexion were analyzed for 2,916 possible cruciate ligament location and length combinations to determine the effects on the A/P stability of the TKR. A physical model was then constructed, and the design was verified by performing 110 N A/P drawer tests under 710 N of simulated body weight. Results and Discussion. As ACL insertion location moved posteriorly on the femur, it was found to decrease ACL ligament strain, enabling a higher range of flexion. In general, as ACL and PCL length increased, the A/P laxity of the TKR system increased linearly. Range of motion was found to be more dependent on ligament attachment location, and laxity was more dependent on ligament length. In this work, TKR stability was clearly affected by changes in synthetic ligament length and location. When comparing the laxity between a TKR with and without ligaments, the TKR with synthetic ligaments experienced significantly less displacement than a TKR without synthetic ligaments. Conclusions. The stability of a TKR can be increased while maintaining range of motion by incorporating synthetic ligaments into its design. The effectiveness of the ligaments was clearly dependent on two factors: length and location. It is imperative to the success of the implant to obtain the correct lengths and locations because improper placement or length can impact the outcome significantly. These results emphasize the need for a knee replacement that incorporates synthetic ligaments, with calibrated location and lengths, to significantly influence stability and possible kinematic performance of the TKR system, and potentially influencing long-term functional outcomes


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 36 - 36
1 May 2016
Meere P Walker P Schneider S Salvadore G Borukhov I
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Introduction. The role of soft tissue balancing in optimizing functional outcome and patient satisfaction after total knee arthroplasty surgery is gaining interest. This is due in part to the inability of pure alignment to demonstrate excellent functional outcomes 6. Consistent soft tissue balancing has been aided by novel technologies that can quantify loads across the joint at the time of surgery 4. In theory, compressive load equilibrium should be correlated with ligamentous equilibrium between the medial and lateral collateral ligaments. The authors propose to use the Collateral Ligaments Strain Ratio (CLSR) as a functional tool to quantify and track surgical changes in laxity of the collateral ligaments and correlate this ratio to validated functional scores and patient reported outcomes. The relationship with intra-operative balancing of compartmental loads can then be scrutinized. The benefits of varus-valgus balancing within 2o include increased range of motion 7, whereas pressure imbalance between the medial and lateral joint compartments has been linked to condylar liftoff and abnormal kinematics post-TKA 8. Methods. The study is a prospective IRB approved clinical study with three cohorts of 50 patients each: (1) a surgical prospective study group (2) a matched control group of non-operated high function patients; (3) a matched control group of high function knee arthroplasty recipients. Standard statistical analysis method is applied. The testing of the CLSR is performed using a validated Smart Knee Brace developed by the authors and previously reported 1. The output variables consist of the maximum angular change of the knee in the coronal plane at 10 degrees of flexion produced by a controlled torque application in the varus and valgus (VV) directions. This creates measureable strain on the lateral and medial collateral ligaments, which is reported as a ratio (CLSR). The New Knee Society Score is used to track outcomes. The intra-operative balance is achieved by means of an instrumented tibial tray (OrthoSensor, Inc). Results. Pre-operative scatter graphs (Fig 1) demonstrate a wide distribution of absolute VV values, reflecting the spectrum of pathological states. The relative distribution of strain after surgery trends towards consolidation. The median CLSR is 0.55 with a SD of 0.20 at 4 weeks post-operative. This asymmetrical value indicates a shift toward a tighter medial side as noted in the non-operated cohort. Scatter graphs demonstrate post-operative clustering similar to that reported by the authors for kinetic loads after soft tissue balancing (Fig 2)3. The overall displacement values range from 0 −4 degrees. Discussion. The angular changes under standard torque appear to correlate with previously reported linear displacement values 3. Past studies do indicate a shift toward a tighter medial side in healthy older individuals, with an average CLSR in extension and flexion of 0.55 5. Success in achieving soft tissue balancing of the knee at the time of arthroplasty surgery may be predicted by a defined collateral ligament strain ratio under controlled VV testing. This study demonstrates clustering of the strain ratio in slight medial tightness with a range of absolute angular displacements of 0–4 degrees


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_5 | Pages 6 - 6
1 Feb 2016
Meere P Schneider S Borukhov I Walker P
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Introduction. The role of soft tissue balancing in optimising functional outcome and patient satisfaction after total knee arthroplasty surgery is gaining interest. Consistent soft tissue balancing has been aided by novel technologies that can quantify loads across the joint at the time of surgery. Based on free body diagram theory, compressive load equilibrium should be correlated with ligamentous equilibrium between the medial and lateral collateral ligaments. The authors propose to use the Collateral Ligaments Strain Ratio (CLSR) as a functional tool to quantify and track the effectuated surgical change in laxity of the medial and lateral collateral ligaments and correlate this ratio to validated functional scores and patient reported outcomes. The relationship with intra-operative balancing of compartmental loads can then be scrutinised. Methods. The study is a prospective clinical study with three cohorts of 50 patients each: (1) a surgical prospective study group with ligamentous testing pre-operatively, at 4 weeks, 3 months and 6 months post-operatively; (2) a matched control group of non-operated high function patients; (3) a matched control group of high function knee arthroplasty recipients. Standard statistical analysis method is applied. The testing of the CLSR is performed using a validated Smart Knee Brace developed by the authors and previously reported. The output variables consist of the maximum angular change of the knee in the coronal plane at 10 degrees of flexion produced by a controlled torque application in the varus and valgus (VV) directions. This creates measureable strain on the lateral and medial collateral ligaments, which is reported as a ratio (CLSR). The New Knee Society Score is used to track outcomes. The intra-operative balance is achieved by means of an instrumented tibial tray (OrthoSensor, Inc). The applied torque was standardised to 10Nm with a handheld wireless dynamometer. Results. Pre-operative scatter graphs demonstrate a wide distribution of absolute VV values, reflecting the spectrum of pathological states. The relative distribution of strain after surgery trends towards consolidation. The median CLSR is 0.55 with a SD of 0.20. This asymmetrical value indicates a shift toward a tighter medial side. The overall displacement values range from 0–4 degrees. The angular changes under standard torque appear to correlate with the linear displacement values previously reported by Bellemans et al


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_16 | Pages 25 - 25
17 Nov 2023
Mok S Almaghtuf N Paxton J
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Abstract

The lateral ligaments of the ankle composed of the anterior talofibular (ATFL), calcaneofibular (CFL) and posterior talofibular ligaments (PTFL), are amongst the most commonly injured ligaments of the human body. Although treatment methods have been explored exhaustively, healing outcomes remain poor with high rates of re-injury, chronic ankle instability and pain persisting. The introduction and application of tissue engineering methods may target poor healing outcomes and eliminate long-term complications, improving the overall quality of life of affected individuals. For any surgical procedure or tissue-engineered replacement to be successful, a comprehensive understanding of the complete anatomy of the native structure is essential. Knowledge of the dimensions of ligament footprints is vitally important for surgeons as it guides the placement of bone tunnels during repair. It is also imperative in tissue-engineered design as the creation of a successful replacement relies on a thorough understanding of the native anatomy and microanatomical structure. Several studies explore techniques to describe ligament footprints around the body, with limited studies describing in-depth footprint dimensions of the ATFL, CFL and PTFL. Techniques currently used to measure ligament footprints are complex and require resources which may not be readily available, therefore a new methodology may prove beneficial.

Objectives

This study explores the application of a novel technique to assess the footprint of ankle ligaments through a straightforward inking method. This method aims to enhance surgical technique and contribute to the development of a tissue-engineered analogue based on real anatomical morphometric data.

Methods

Cadaveric dissection of the ATFL, CFL and PTFL was performed on 12 unpaired fresh frozen ankles adhering to regulations of the Human Tissue (Scotland) Act. The ankle complex with attaching ligaments was immersed in methylene blue. Dissection of the proximal and distal entheses of each ligament was carried out to reveal the unstained ligament footprint. Images of each ligament footprint were taken, and the area, length and width of each footprint were assessed digitally.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXI | Pages 79 - 79
1 May 2012
Q.A. F N. A
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Carpal bone mechanics are complex and poorly understood. An anatomic model that explains observed kinematic results is yet to be achieved. The aim of this study is to determine if morphologic sub-typing of the STT and TH joints exists. The study used 100 sets of dry disarticulated carpal bones and 50 cadaveric wrists. A digital microscribe was used to reconstruct and measure the articular surfaces of the STT and TH joints and distal lunate of all specimens. Ligaments were dissected, reconstructed and measured. Lunate typing based on the morphology of the distal articular surface allowed the specimens to be split into three groups: type one lunates (single facet; 30%), type two lunates (double facet; 42%) and unclear (intermediate; type three; 28%). Type one and type two groups had significantly different (p < 0.05) mean measures at the STT and TH joints, suggesting clear differences in joint shape and hence joint motion. Type three had mean measures that were not significantly different (p>0.05) from either of the other groups. Two distinct ligament patterns were also observed. The mean measures of each ligament were significantly different (p< 0.05) between type one and two specimens. Type three specimens were split into those with a ligamentous pattern similar to type one specimens and those similar to type two, each significantly different from each other (p< 0.05). Type one specimens had ‘sling-like’ supports for either side of the wrist, whilst type two specimens had numerous attachments to the scaphoid and hamate, creating potential points of rotation. These results suggest that bony typing gives a clear indication of potential carpal motion for 72% of cases. The remaining 28% are reliant upon ligamentous typing. Individuals are predisposed to structurally support one pattern of motion. Further investigation will relate these anatomic differences to observable motion


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_16 | Pages 40 - 40
17 Nov 2023
Kuder I Jones G Rock M van Arkel R
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Abstract

Objectives

Ultrasound speckle tracking is a safe and non-invasive diagnostic tool to measure soft tissue deformation and strain. In orthopaedics, it could have broad application to measure how injury or surgery affects muscle, tendon or ligament biomechanics. However, its application requires custom tuning of the speckle-tracking algorithm then validation against gold-standard reference data. Implementing an experiment to acquire these data takes months and is expensive, and therefore prohibits use for new applications. Here, we present an alternative optimisation approach that automatically finds suitable machine and algorithmic settings without requiring gold-standard reference data.

Methods

The optimisation routine consisted of two steps. First, convergence of the displacement field was tested to exclude the settings that would not track the underlying tissue motion (e.g. frame rates that were too low). Second, repeatability was maximised through a surrogate optimisation scheme. All settings that could influence the strain calculation were included, ranging from acquisition settings to post-processing smoothing and filtering settings, totalling >1,000,000 combinations of settings. The optimisation criterion minimised the normalised standard deviation between strain maps of repeat measures. The optimisation approach was validated for the medial collateral ligament (MCL) with quasi-static testing on porcine joints (n=3), and dynamic testing on a cadaveric human knee (n=1, female, aged 49). Porcine joints were fully dissected except for the MCL and loaded in a material-testing machine (0 to 3% strain at 0.2 Hz), which was captured using both ultrasound (>14 repeats per specimen) and optical digital image correlation (DIC). For the human cadaveric knee (undissected), 3 repeat ultrasound acquisitions were taken at 18 different anterior/posterior positions over the MCL while the knee was extended/flexed between 0° and 90° in a knee extension rig. Simultaneous optical tracking recorded the position of the ultrasound transducer, knee kinematics and the MCL attachments (which were digitised under direct visualisation post testing). Half of the data collected was used for optimisation of the speckle tracking algorithms for the porcine and human MCLs separately, with the remaining unseen data used as a validation test set.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_2 | Pages 40 - 40
1 Mar 2021
Karunaseelan KJ van Arkel R Jeffers J
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Abstract

Objectives

Hip joint laxity after total hip arthroplasty (THA) has been considered to cause microseparation and lead to complications, including wear and dislocation. In the native hip, the hip capsular ligaments may tighten at the limits of range of hip motion and provide a passive stabilising force preventing edge loading and reduce the risk of dislocation. Previous attempts to characterise mechanical properties of hip capsular ligaments have been largely variable and there are no cadaveric studies quantifying the force contributions of each ligament in different hip positions. In this study we quantify the passive force contribution of the hip capsular ligaments throughout a complete range of motion (ROM).

Methods

Nine human cadaveric hip specimens (6 males and 3 females) with mean age of (76.4 ± 9.0 years) were skeletonised, preserving the capsular ligaments. Prepared specimens were tested in a 6 degree of freedom system to assess ROM with 5 Nm torque applied in external and internal rotation throughout hip flexion and extension. Capsular ligaments were resected in a stepwise fashion to assess internal force contributions of the iliofemoral (superior and inferior), pubofemoral, and ischiofemoral ligaments during ROM.


Bone & Joint Research
Vol. 10, Issue 9 | Pages 594 - 601
24 Sep 2021
Karunaseelan KJ Dandridge O Muirhead-Allwood SK van Arkel RJ Jeffers JRT

Aims

In the native hip, the hip capsular ligaments tighten at the limits of range of hip motion and may provide a passive stabilizing force to protect the hip against edge loading. In this study we quantified the stabilizing force vectors generated by capsular ligaments at extreme range of motion (ROM), and examined their ability to prevent edge loading.

Methods

Torque-rotation curves were obtained from nine cadaveric hips to define the rotational restraint contributions of the capsular ligaments in 36 positions. A ligament model was developed to determine the line-of-action and effective moment arms of the medial/lateral iliofemoral, ischiofemoral, and pubofemoral ligaments in all positions. The functioning ligament forces and stiffness were determined at 5 Nm rotational restraint. In each position, the contribution of engaged capsular ligaments to the joint reaction force was used to evaluate the net force vector generated by the capsule.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_1 | Pages 51 - 51
1 Feb 2021
Smith L Cates H Freeman M Nachtrab J Komistek R
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Background

While posterior cruciate retaining (PCR) implants are a more common total knee arthroplasty (TKA) design, newer bi-cruciate retaining (BCR) TKAs are now being considered as an option for many patients, especially those that are younger. While PCR TKAs remove the ACL, the BCR TKA designs keep both cruciate ligaments intact, as it is believed that the resection of the ACL greatly affects the overall kinematic patterns of TKA designs. Various fluoroscopic studies have focused on determination of kinematics but haven't defined differentiators that affect motion patterns. This research study assesses the importance of the cruciate ligaments and femoral geometry for Bi-Cruciate Retaining (BCR) and Posterior Cruciate Retaining (PCR) TKAs having the same femoral component, compared to the normal knee.

Methods

The in vivo 3D kinematics were determined for 40 subjects having a PCR TKA, 10 having a BCR TKA, and 10 having a normal knee, in a retrospective study. All TKA subjects had the same femoral component. All subjects performed a deep knee bend under fluoroscopic surveillance. The kinematics were determined during early flexion (ACL dominant), mid flexion (ACL/PCL transition) and deep flexion (PCL dominant).


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_1 | Pages 4 - 4
1 Feb 2021
Coomer S LaCour M Khasian M Cates H Komistek R
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Introduction

The patella experiences large forces and variable kinematic patterns throughout flexion which could influence function and patient satisfaction after a total knee arthroplasty (TKA). Therefore, the objective of this study is to analyze in vivo patellar mechanism forces and kinematics throughout flexion to determine influencing factors that may lead to patient dissatisfaction.

Methods

Fifty subjects were evaluated in this study, 40 having a Journey II bi-cruciate stabilized (BCS) TKA and 10 having normal, healthy knees. Similar demographics were controlled for each group. Each subject performed a deep knee bend. Kinematics were evaluated using a validated 3D-to-2D fluoroscopic technique while forces were determined using a validated inverse mathematical knee model. A two-tailed t-test was used to evaluate statistical significance.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_20 | Pages 57 - 57
1 Dec 2017
Péan F Carrillo F Fürnstahl P Goksel O
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The Interosseous Membrane (IOM) of the forearm is made up of ligaments, which are involved in load balancing of the radioulnar joint and the shaft. Motion models of the forearm are necessary for planning orthopedic surgeries, such as osteotomies, which aim at solving limit of the range of motion or instabilities. However, existing models focus on a pure kinematic approach, omitting the physical properties of the ligaments, thus limiting the range of application by missing dynamical effects.

We developed a model that takes into account the mechanical properties of the IOM. We simulated the pro-supination by creating an elastic coupling to the desired motion around the standard axis of rotation. We tested our model on a healthy subject, using CT-reconstructed bone models, and literature data for the ligaments. Multiple parameters, including forces of ligaments and positions of landmarks, are output for analysis.

The length of the ligaments over pro-supination was in agreement with the literature. Their rest lengths must be recorded in future anatomical studies. The IOM helps in maintaining the contact with cartilage, except in late pronation. Scarring of the central band increases the force generated along the axis of rotation toward the wrist, while scarring of the proximal part does the opposite in pronation.

In contrast to kinematic models, the proposed model is helpful to study the effect of physical properties of the IOM, such scarring, on the forearm motion. Future work will be to apply our model to pathological cases, and to compare to clinical observations.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_2 | Pages 15 - 15
1 Jan 2019
Rochelle D Herbert A Ktistakis I Redmond AC Chapman G Brockett CL
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Whilst lateral ankle sprain is often considered a benign injury it represents between 3–5% of all A&E visits in the UK. The mechanical characteristics of ankle ligaments under sprain-like conditions are scarcely reported.

The lateral collateral ankle ligaments were dissected from n=6 human cadaveric specimens to produce individual bone-ligament-bone specimens. An Instron Electropuls E10000 was used to uni-axially load the ankle ligaments in tension. The ligaments were first preconditioned between 2 N and a load value corresponding to 3.5% strain for 15 cycles and then strained to failure at a rate of 100%/s.

The mean ultimate failure loads and their standard deviations for the anterior talofibular (ATFL), calcaneofibular (CFL) and posterior talofibular (PTFL) ligaments are 351.4±105.6 N, 367.8±76.1 N and 263.6±156.6 N, respectively. Whilst the standard deviation values are high they align with those previously reported for ankle ligament characterisation. The large standard deviations are partly due to the inherent variability of human cadaveric tissue but could also be due to varying previous activity levels of participants or a prior unreported ankle sprain. Although the sample size is relatively small the results were stratified to identify any potential correlations of age, BMI and weight with ultimate load. A strong Pearson correlation (r=0.919) was found between BMI and ultimate load of the CFL but a larger sample size is required to confirm a link. The ligament failure modes were observed and categorised as avulsion or intra-ligamentous failure. The ATFL avulsed from the fibula in five instances and intra-ligamentous failure occurred once. The CFL avulsed from the fibula twice and failed four times through intra-ligamentous failure. Finally, the PTFL avulsed from the fibula once, avulsed from the talus once and failed through intra-ligamentous failure in four instances.

The results identify the forces required to severely sprain the lateral collateral ankle ligaments and their failure modes.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_5 | Pages 65 - 65
1 Apr 2018
DesJardins J Stokes M Pietrykowski L Gambon T Greene B Bales C
Full Access

Introduction

There are over one-half million total knee replacement (TKR) procedures performed each year in the United States and is projected to increase to over 3.48 million by 2030. Concurrent with the increase in TKR procedures is a trend of younger patients receiving knee implants (under the age of 65). These younger patients are known to have a 5% lower implant survival rate at 8 years post-op compared to older patients (65+ years), and they are also known to live more active lifestyles that place higher demands on the durability and functional performance of the TKR device. Conventional TKR designs increase articular conformity to increase stability, but these articular constraints decrease patient range of knee motion, often limiting key measures of femoral rollback, A/P motion, and deep knee flexion. Without this articular constraint however, many patients report TKR “instability” during activities such as walking and stair descent, which can significantly impede confidence of movement. Therefore there is a need for a TKR system that can offer enhanced stability while also maintaining active ranges of motion.

Materials and Methods

A novel knee arthroplasty system was designed that uses synthetic ligament systems that can be surgically replaced, to provide ligamentous stability and natural motion to increase the functional performance of the implant. Using an anatomical knee model from the AnyBody software, a computational model that incorporated ligaments into an existing Journey II TKR was developed. Using the software ligaments were modeled and given biomechanical properties developed from equations from literature. Simulated A/P drawer tests and knee flexion test were analyzed for 2,916 possible cruciate ligament location and length combinations to determine the effects on the A/P stability of the TKR. A physical model was constructed, and the design was verified by performing 110 N A/P drawer tests under 710 N of simulated body weight.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 178 - 178
1 Dec 2013
Takai S Iizawa N Kawaji H
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Anterior cruciate ligament (ACL) of four major knee ligaments is most crucial ligament to maintain normal knee kinematics. It is well know that ACL dysfunction causes secondary osteoarthritis of the knee. The influence of age on the biomechanical properties of the ACL was examined. The structural properties of 27 pairs of human cadaver knees without OA were evaluated. Specimens were equally divided into three groups of nine pairs each based on age: younger (22 to 35 years), middle (40 to 50 years), and older (60 to 97 years). Tensile tests of the femur-ACL-tibia complex were performed at 30 degrees of knee flexion with the ACL aligned vertically along the direction of applied tensile load. Structural properties of the femur-ACL-tibia complex, as represented by the linear stiffness, ultimate load, and energy absorbed, were found to decrease significantly with specimen age.

On the other hand, little has been written about the arthritic ACL. This study was designed to evaluate the relationship among ROM, cross sections of the intercondylar notch and the macroscopic condition of ACL degeneration. Fifty osteoarthritic patients who underwent TKA as a result of severe osteoarthritis were randomly selected. Occupation rate of the osteophytes to the notch width were measured at the anterior 1/3, middle 1/3, and posterior 1/3 notche images obtained from preoperative tunnel view. ROM was measured preoperatively and under anesthesia. Macroscopic conditions of the ACL and PCL were classified into four types of Normal, Frayed, Partial rupture, and Absent.

The macroscopic ACL conditions were Normal: 12 cases, Frayed: 15 cases, Partial rupture: 14 cases, and Absent: 9 cases. The macroscopic PCL conditions were Normal: 34 cases, Frayed: 9 cases, Partial rupture: 7 cases, and Absent: 0 case. Occupation rate of the osteophytes to the notch correlated to the preoperative varus deformity (p < 0.05). In terms of ACL, the occupation rate of the osteophytes to the notch were 22.9%, 28.8%, 46.0%, and 81.8% in Normal, Frayed, partial ruptured, and Absent, respectively. The patients with more than 40% occupation rate and less than 110 degree of knee flexion angle showed either partial rupture or absent of the ACL during the surgery. Those results correlated with the degree of OA deterioration. We conclude that occupation rate of the osteophytes to the notch poor preoperative ROM is a good predictor of evaluating the ACL degeneration in osteoarthritic knee. We also conclude that ACL dysfunction due to joint space narrowing accelerates the advancement of the knee OA.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 321 - 321
1 Nov 2002
Gupte CM Smith A McDermott ID Bull AMJ Thomas RD Amis AA
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Aim: To accurately identify the meniscofemoral ligaments in cadaveric human specimens, and to determine anatomical variations in the posterior cruciate ligament that may lead to mis-identification of these structures.

Methods: A total of 79 fresh frozen knees were examined from 45 cadavers Combined anterior and posterior approaches were used to inspect the vicinity of the posterior cruciate ligament (PCL) for the presence of the anterior and posterior meniscofemoral ligaments. The anterior approach utilised a medial parapatellar incision followed by division of the anterior cruciate ligament, whilst a midline posterior arthrotomy was used for the posterior approach. Further dissection facilitated inspection of the meniscal and femoral attachments of the MFLs, and measurement of their lengths. Videos of MFL and PCL motion during passive flexion of the cadaveric were also performed.

Results: In total, 74 (94%) of the 79 specimens contained at least one meniscofemoral ligament. The posterior meniscofemoral ligament (pMFL) was present in 56 (71%) specimens, whilst the anterior meniscofemoral ligament (aMFL) was present in 58 specimens (73%). Both ligaments coexisted in 40 (51%) of knees. In 15 specimens the PCL was seen to have oblique fibres, which attached proximal to the tibial attachment of the main part of the PCL. We termed this “the false pMFL”, as it could be easily mis-identified as the posterior meniscofemoral ligament. Several other anatomical variations were also identified. The mean length of the aMFL was 20.7±3.9mm, whilst that of the pMFL was 23±4.2mm. Although the lengths of the MFLs were relatively constant, there was a wide variation in thickness.

Discussion: This study confirms the high incidence of at least one MFL in humans, which suggests a functional role for these structures. The oblique fibres of the PCL can be readily mis-identfied as the pMFL. These caveats should be borne in mind, during both arthroscopic examination and in the interpretation of magnetic resonance imaging (MRI) scans of the knee. Although some variations of the MFLs have been reported on MRI imaging2, there has been no note of the oblique fibres of the PCL reported in the present study. As this variation was present in almost one in five of our specimens, its appearance on MRI scanning requires investigation.

The function of the meniscofemoral ligaments is undetermined, although many hypotheses comment on a role in guiding the motion of the lateral meniscus during knee flexion. Other possibilities include a function as a secondary restraint supplementing the posterior cruciate ligament.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_II | Pages 324 - 324
1 May 2010
Ostadal M
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Aims: Congenital aplasia of the knee cruicate ligaments is considered to be a very rare anomaly of musculoskeletal system. It is frequently found in conjunction with other deformities. Proximal femoral focal deficiency (PFFD) is a congenital defect which is almost always accompanied by cruciate ligament defect.

The aim of our study was to determine the occurence of cruciate ligament aplasia arthroscopically.

Method: Arthroscopies of the knee joints were always performed as part of other primary operations for PFFD.

In our followed series consisting of 50 PFFD patients, 26 boys and 24 girls, five boys with PFFD classified respectively as Pappas III, VII, VII, VIII and IX and 3 girls with PFFD classified respectively as Pappas III, VII and VIII were examined arthroscopically. Deficiency of cruciate ligaments was also documented in a pateint with the diagnosis of isolated aplasia of the fibula.

Changes in the shape of intercondylar area of the distal femur, and aplasia or hypoplasia of the intercondylar ridge of proximal tibia in all PFFD patients were evaluated by an X-ray.

Conclusions: In all patients who underwent arthroscopy absence of both cruciate ligaments was proven.

Seriousness of the anomaly was inversely related to the degree of classification according to Pappas. None of our patients suffered from problems arising from knee instability. Based on our experience we recommend a reserved approach as far an indication for cruciate ligament reconstruction in PFFD patients is concerned.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 222 - 222
1 Dec 2013
Agueci A Mariani C
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The Authors present a ligament tensor for the evaluation of the ligaments balance used during the implant of total knee prosthesis, which is able to suggest the orientation of the bone resection, not only in knee flexion, but also in extention. This instrument provides for the placement of the endomedullary rod equipped (figures 1 and 2) with a plate of various valgus levels on which, the balancing part of the tensor, is pushing against, while the stable part is leaning against the tibial resected surface (figure 3).

This system allows to choose the right valgus level, without having to recur to the ligamentous lysis, if so only minimum, and above all, allows this way to aviod the error of orienting the distal femoral resection due to the imperfect coaxiality between the endomedullary rod and the femoral canal. This mistake might happen because of the imperfect point of entrance and/or because of a not so small difference between the rod caliber and the femoral canal width.


Orthopaedic Proceedings
Vol. 86-B, Issue SUPP_I | Pages 100 - 100
1 Jan 2004
Brownlow H Freemont A Even T Copeland S Levy O
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The coraco-acromial ligament (CAL) is partially resected during a subacromial decompression. Clinical studies have reported the regeneration of a structure which appears to be a new CAL. Histological studies of regenerated CAL have demonstrated an abundance of relatively acellular collagen fibrils orientated in the line of a ligament and mechanical testing of the regenerated tissue has properties similar to those of normal CAL. However it is still not clear whether this structure represents scar tissue or truly reformed ligament. Defining the major collagen constituent of this regenerated tissue would allow the distinction between ligament and scar tissue. Therefore the aim of this study was to examine the level of expression of types I and III collagen in regenerated coraco-acromial ligaments (CAL) in humans.

Samples of regenerated CAL were obtained during open surgery for repair of small rotator cuff tears at an average of 24 months (range 14 to 52) after arthroscopic subacromial decompression from 4 men and 3 women with an average age of 58 years (range 44 to 68). A standard protocol radio-active in-situ immunolocalisation technique was used to quantify the ratios of mRNA collagen I to collagen III in the samples.

The results demonstrated that the average ratio of collagen I to collagen III was 6.5. This ratio is similar to the value for normal hip capsule (5–6:1) and human posterior cruciate ligament (8:1).

We conclude that the reformed CALs are ligamentous structures, not scar tissue, and therefore represent truly regenerated ligaments.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_6 | Pages 100 - 100
1 Mar 2017
Wimmer M Simon J Kawecki R Della Valle C
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Introduction

Preservation of the anterior cruciate ligament (ACL), along with the posterior cruciate ligament, is believed to improve functional outcomes in total knee replacement (TKR). The purpose of this study was to examine gait differences and muscle activation levels between ACL sacrificing (ACL-S) and bicruciate retaining (BCR) TKR subjects during level walking, downhill walking, and stair climbing.

Methods

Ten ACL-S (Vanguard CR) (69±8 yrs, 28.7±4.7 kg/m2) and eleven BCR (Vanguard XP, Zimmer-Biomet) (63±11 yrs, 31.0±7.6 kg/m2) subjects participated in this IRB approved study. Except for the condition of the ACL, both TKR designs were similar. Subjects were tested 8–14 months post-op in a motion analysis lab using a point cluster marker set and surface electrodes applied to the Vastus Medialis Oblique (VMO), Rectus Femoris (RF), Biceps Femoris (BF) and Semitendinosus (ST). 3D motion and force data and electromyography (EMG) data were collected simultaneously. Subjects were instructed to walk at a comfortable walking speed across a walkway, down a 12.5% downhill slope, and up a staircase. Five trials per activity were collected. Knee kinematics and kinetics were analyzed using BioMove (Stanford, Stanford, CA). The EMG dataset underwent full-wave rectification and was smoothed using a 300ms RMS window. Gait cycle was time normalized to 100%; relative voluntary contraction (RVC) was calculated by dividing the average activation during downhill walking by the maximum EMG value during level walking and multiplying by 100%.