Publications
470 results found
Stephen JM, Kittl C, Williams A, et al., 2016, Effect of medial patellofemoral ligament reconstruction method on patellofemoral contact pressures and kinematics., American Journal of Sports Medicine, Vol: 44, Pages: 1186-1194, ISSN: 1552-3365
BACKGROUND: There remains a lack of evidence regarding the optimal method when reconstructing the medial patellofemoral ligament (MPFL) and whether some graft constructs can be more forgiving to surgical errors, such as overtensioning or tunnel malpositioning, than others. HYPOTHESIS: The null hypothesis was that there would not be a significant difference between reconstruction methods (eg, graft type and fixation) in the adverse biomechanical effects (eg, patellar maltracking or elevated articular contact pressure) resulting from surgical errors such as tunnel malpositioning or graft overtensioning. STUDY DESIGN: Controlled laboratory study. METHODS: Nine fresh-frozen cadaveric knees were placed on a customized testing rig, where the femur was fixed but the tibia could be moved freely from 0° to 90° of flexion. Individual quadriceps heads and the iliotibial tract were separated and loaded to 205 N of tension using a weighted pulley system. Patellofemoral contact pressures and patellar tracking were measured at 0°, 10°, 20°, 30°, 60°, and 90° of flexion using pressure-sensitive film inserted between the patella and trochlea, in conjunction with an optical tracking system. The MPFL was transected and then reconstructed in a randomized order using a (1) double-strand gracilis tendon, (2) quadriceps tendon, and (3) tensor fasciae latae allograft. Pressure maps and tracking measurements were recorded for each reconstruction method in 2 N and 10 N of tension and with the graft positioned in the anatomic, proximal, and distal femoral tunnel positions. Statistical analysis was undertaken using repeated-measures analyses of variance, Bonferroni post hoc analyses, and paired t tests. RESULTS: Anatomically placed grafts during MPFL reconstruction tensioned to 2 N resulted in the restoration of intact medial joint contact pressures and patellar tracking for all 3 graft types investigated (P > .050). However, femoral tunnels positioned proxim
Ghosh KM, Manning WA, Blain AP, et al., 2016, Influence of increasing construct constraint in the presence of posterolateral deficiency at knee replacement: A biomechanical study, JOURNAL OF ORTHOPAEDIC RESEARCH, Vol: 34, Pages: 427-434, ISSN: 0736-0266
- Author Web Link
- Cite
- Citations: 7
Stephen JM, Kader D, Lumpaopong P, et al., 2016, The effect of femoral tunnel position and graft tension on patellar contact mechanics and kinematics after medial patellofemoral ligament reconstruction (vol 42, pg 364, 2014), AMERICAN JOURNAL OF SPORTS MEDICINE, Vol: 44, Pages: NP11-NP11, ISSN: 0363-5465
- Author Web Link
- Cite
- Citations: 1
Kittl C, El-Daou H, Athwal KK, et al., 2016, The role of the anterolateral structures and the ACL in controlling laxity of the intact and ACL-deficient knee, AMERICAN JOURNAL OF SPORTS MEDICINE, Vol: 44, Pages: 345-354, ISSN: 0363-5465
Background:Anterolateral rotatory instability (ALRI) may result from combined anterior cruciate ligament (ACL) and lateral extra-articular lesions, but the roles of the anterolateral structures remain controversial.Purpose:To determine the contribution of each anterolateral structure and the ACL in restraining simulated clinical laxity in both the intact and ACL-deficient knee.Study Design:Controlled laboratory study.Methods:A total of 16 knees were tested using a 6 degrees of freedom robot with a universal force-moment sensor. The system automatically defined the path of unloaded flexion/extension. At different flexion angles, anterior-posterior, internal-external, and internal rotational laxity in response to a simulated pivot shift were tested. Eight ACL-intact and 8 ACL-deficient knees were tested. The kinematics of the intact/deficient knee was replayed after transecting/resecting each structure of interest; therefore, the decrease in force/torque reflected the contribution of the transected/resected structure in restraining laxity. Data were analyzed using repeated-measures analyses of variance and paired t tests.Results:For anterior translation, the intact ACL was clearly the primary restraint. The iliotibial tract (ITT) resisted 31% ± 6% of the drawer force with the ACL cut at 30° of flexion; the anterolateral ligament (ALL) and anterolateral capsule resisted 4%. For internal rotation, the superficial layer of the ITT significantly restrained internal rotation at higher flexion angles: 56% ± 20% and 56% ± 16% at 90° for the ACL-intact and ACL-deficient groups, respectively. The deep layer of the ITT restrained internal rotation at lower flexion angles, with 26% ± 9% and 33% ± 12% at 30° for the ACL-intact and ACL-deficient groups, respectively. The other anterolateral structures provided no significant contribution. During the pivot-shift test, the ITT provided 72% ± 14% of the restraint at 45° for th
Stephen JM, Halewood C, Kittl C, et al., 2016, Posteromedial Meniscocapsular Lesions Increase Tibiofemoral Joint Laxity With Anterior Cruciate Ligament Deficiency, and Their Repair Reduces Laxity, American Journal of Sports Medicine, Vol: 44, Pages: 400-408, ISSN: 0363-5465
Background:Injury to the posteromedial meniscocapsular junction has been identified after anterior cruciate ligament (ACL) rupture; however, there is a lack of objective evidence investigating how this affects knee kinematics or whether increased laxity can be restored by repair. Such injury is often overlooked at surgery, with possible compromise to results.Hypotheses:(1) Sectioning the posteromedial meniscocapsular junction in an ACL-deficient knee will result in increased anterior tibial translation and rotation. (2) Isolated ACL reconstruction in the presence of a posteromedial meniscocapsular junction lesion will not restore intact knee laxity. (3) Repair of the posteromedial capsule at the time of ACL reconstruction will reduce tibial translation and rotation to normal. (4) These changes will be clinically detectable.Study Design:Controlled laboratory study.Methods:Nine cadaveric knees were mounted in a test rig where knee kinematics were recorded from 0° to 100° of flexion by use of an optical tracking system. Measurements were recorded with the following loads: 90-N anterior-posterior tibial forces, 5-N·m internal-external tibial rotation torques, and combined 90-N anterior force and 5-N·m external rotation torque. Manual Rolimeter readings of anterior translation were taken at 30° and 90°. The knees were tested in the following conditions: intact, ACL deficient, ACL deficient and posteromedial meniscocapsular junction sectioned, ACL deficient and posteromedial meniscocapsular junction repaired, ACL patellar tendon reconstruction with posteromedial meniscocapsular junction repair, and ACL reconstructed and capsular lesion re-created. Statistical analysis used repeated-measures analysis of variance and post hoc paired t tests with Bonferroni correction.Results:Tibial anterior translation and external rotation were both significantly increased compared with the ACL-deficient knee after posterior meniscocapsular sectioning (P <
Lord B, Amis AA, 2016, The envelope of laxity of the pivot shift test, Rotatory Knee Instability: An Evidence Based Approach, Pages: 223-234, ISBN: 9783319320694
The pivot shift is a dynamic test of knee laxity which correlates with subjective sensations of knee instability. As the knee flexes from full extension, the tibia subluxes, both in anterior translation and internal rotation, so that the lateral femoral condyle moves ‘downhill’ to the posterior edge of the tibial plateau under the influence of the compressive joint load. With further knee flexion, the tension in the iliotibial tract eventually overcomes the load which has maintained the subluxation and then the tibia is suddenly reduced to its anatomical articulation. Thus, the envelope of laxity of the pivot shift shows a pattern of simultaneous gradual pathological anterior translation and internal rotation, occurring over approximately 35° of knee flexion, followed by a relatively sudden reduction, which is a falling back posteriorly and externally to the anatomical position. It is desirable to measure both tibial translations and rotations to understand each injured knee, because differing patterns of injury may explain the wide range of tibiofemoral movements, such as the relative amount of tibial translation versus rotation, that have been reported during the pivot shift.
Barcellona MG, Morrissey MC, Milligan P, et al., 2015, The effect of knee extensor open kinetic chain resistance training in the ACL-injured knee, KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY, Vol: 23, Pages: 3168-3177, ISSN: 0942-2056
- Author Web Link
- Cite
- Citations: 3
Athwal KK, Daou HE, Kittl C, et al., 2015, The superficial medial collateral ligament is the primary medial restraint to knee laxity after cruciate-retaining or posterior-stabilised total knee arthroplasty: effects of implant type and partial release., Knee Surgery, Sports Traumatology, Arthroscopy, Vol: 24, Pages: 2646-2655, ISSN: 0942-2056
PURPOSE: The aim of this study was to quantify the contributions of medial soft tissues to stability following cruciate-retaining (CR) or posterior-stabilised (PS) total knee arthroplasty (TKA). METHODS: Using a robotic system, eight cadaveric knees were subjected to ±90-N anterior-posterior force, ±5-Nm internal-external and ±8-Nm varus-valgus torques at various flexion angles. The knees were tested intact and then with CR and PS implants, and successive cuts of the deep and superficial medial collateral ligaments (dMCL, sMCL) and posteromedial capsule (PMC) quantified the percentage contributions of each structure to restraining the applied loads. RESULTS: In implanted knees, the sMCL restrained valgus rotation (62 % across flexion angles), anterior-posterior drawer (24 and 10 %, respectively) and internal-external rotation (22 and 37 %). Changing from CR TKA to PS TKA increased the load on the sMCL when resisting valgus loads. The dMCL restrained 11 % of external and 13 % of valgus rotations, and the PMC was significant at low flexion angles. CONCLUSIONS: This work has shown that medial release in the varus knee should be minimised, as it may inadvertently result in a combined laxity pattern. There is increasing interest in preserving constitutional varus in TKA, and this work argues for preservation of the sMCL to afford the surgeon consistent restraint and maintain a balanced knee for the patient.
Chong DYR, Hansen UN, Amis AA, 2015, CEMENTLESS MIS MINI-KEEL PROSTHESIS REDUCES INTERFACE MICROMOTION VERSUS STANDARD STEMMED TIBIAL COMPONENTS, Journal of Mechanics in Medicine and Biology, Vol: 16, ISSN: 0219-5194
Fixation strength of the cementless knee prostheses is dependent on the initial stability of the fixation and minimal relative motion across the prosthesis–bone interface. Broad mini-keels have been developed for tibial components to allow minimally invasive knee arthroplasty, but the effect of the change in fixation design is unknown. In this study, bone–prosthesis interface micromotions of the mini-keel tibial components (consisting of two designs; one is stemless and another with a stem extension of 45mm) induced by walking and stair climbing were investigated by finite element modeling and compared with standard stemmed design. The prosthesis surface area amenable for bone ingrowth for the mini-keel tibial components (both stemmed and unstemmed) was predicted to be at least 67% larger than the standard stemmed implant, thereby reducing the risk of long-term aseptic loosening. It was also found that while different load patterns may have led to diverse predictions of the magnitude of the interface micromotions and the extent of osseointegration onto the prosthesis, the outcome of design change evaluation in cementless tibial fixations remains unchanged. The mini-keel tibial components were predicted to anchor onto the periprosthetic bone better than the standard stemmed design under all loading conditions investigated.
Masouros S, Halewood C, Bull A, et al., 2015, Biomechanics, Expertise orthopadie und unfallchirurgie: Knie, Editors: Kohn, ISBN: 978-3-1317500-1-3
Geraldes D, Hansen U, Amis A, 2015, An automated framework for parametric analysis glenoid implant design, Bath Biomechanics Symposium 2015
Geraldes D, Hansen U, Amis A, 2015, Parametric analysis of glenoid implant design, International Society of Biomechanics 2015
Simpson RL, Nazhat SN, Blaker JJ, et al., 2015, A comparative study of the effects of different bioactive fillers in PLGA matrix composites and their suitability as bone substitute materials: a thermo-mechanical and in vitro investigation, Journal of The Mechanical Behavior of Biomedical Materials, Vol: 50, Pages: 277-289, ISSN: 1751-6161
Bone substitute composite materials with poly(L-lactide-co-glycolide) (PLGA) matrices and four different bioactive fillers: CaCO3, hydroxyapatite (HA), 45S5 Bioglass(®) (45S5 BG), and ICIE4 bioactive glass (a lower sodium glass than 45S5 BG) were produced via melt blending, extrusion and moulding. The viscoelastic, mechanical and thermal properties, and the molecular weight of the matrix were measured. Thermogravimetric analysis evaluated the effect of filler composition on the thermal degradation of the matrix. Bioactive glasses caused premature degradation of the matrix during processing, whereas CaCO3 or HA did not. All composites, except those with 45S5 BG, had similar mechanical strength and were stiffer than PLGA alone in compression, whilst all had a lower tensile strength. Dynamic mechanical analysis demonstrated an increased storage modulus (E') in the composites (other than the 45S5 BG filled PLGA). The effect of water uptake and early degradation was investigated by short-term in vitro aging in simulated body fluid, which indicated enhanced water uptake over the neat polymer; bioactive glass had the greatest water uptake, causing matrix plasticization. These results enable a direct comparison between bioactive filler type in poly(α-hydroxyester) composites, and have implications when selecting a composite material for eventual application in bone substitution.
Sukjamsri C, Amis A, Hansen UN, et al., 2015, Digital volume correlation and micro-CT: an in-vitro technique for measuring full-field interface micromotion around polyethylene implants, Journal of Biomechanics, Vol: 48, Pages: 3447-3454, ISSN: 0021-9290
Micromotion around implants is commonly measured using displacement-sensor techniques. Due to the limitations of these techniques, an alternative approach (DVC-μCT) using digital volume correlation (DVC) and micro-CT (μCT) was developed in this study. The validation consisted of evaluating DVC-μCT based micromotion against known micromotions (40, 100 and 150 μm) in a simplified experiment. Subsequently, a more clinically realistic experiment in which a glenoid component was implanted into a porcine scapula was carried out and the DVC-μCT measurements during a single load cycle (duration 20 min due to scanning time) was correlated with the manual tracking of micromotion at 12 discrete points across the implant interface. In this same experiment the full-field DVC-μCT micromotion was compared to the full-field micromotion predicted by a parallel finite element analysis (FEA). It was found that DVC-μCT micromotion matched the known micromotion of the simplified experiment (average/peak error=1.4/1.7 μm, regression line slope=0.999) and correlated with the micromotion at the 12 points tracked manually during the realistic experiment (R2=0.96). The DVC-μCT full-field micromotion matched the pattern of the full-field FEA predicted micromotion. This study showed that the DVC-μCT technique provides sensible estimates of micromotion. The main advantages of this technique are that it does not damage important parts of the specimen to gain access to the bone–implant interface, and it provides a full-field evaluation of micromotion as opposed to the micromotion at just a few discrete points. In conclusion the DVC-μCT technique provides a useful tool for investigations of micromotion around plastic implants.
van Arkel R, Amis A, Jeffers J, 2015, The envelope of passive motion allowed by the capsular ligaments of the hip, Journal of Biomechanics, Vol: 48, Pages: 3803-3809, ISSN: 1873-2380
Laboratory data indicate the hip capsular ligaments prevent excessive range of motion, mayprotect the joint against adverse edge loading and contribute to synovial fluid replenishmentat the cartilage surfaces of the joint. However, their repair after joint preserving orarthroplasty surgery is not routine. In order to restore their biomechanical function after hipsurgery, the positions of the hip at which the ligaments engage, together with their tensionswhen they engage is required. Nine cadaveric left hips without pathology were skeletonisedexcept for the hip joint capsule and mounted in a six-degrees-of-freedom testing rig. A 5Nmtorque was applied to all rotational degrees-of-freedom separately to quantify the passiverestraint envelope throughout the available range of motion with the hip functionally loaded.The capsular ligaments allowed the hip to internally/externally rotate with a large range ofun-resisted rotation (up to 50±10°) in mid-flexion and mid-ab/adduction but this was reducedtowards the limits of flexion/extension and ab/adduction such that there was a near-zeroslack region in some positions (p<0.014). The slack region was not symmetrical; the midslackpoint was found with internal rotation in extension and external rotation in flexion(p<0.001). The torsional stiffness of the capsular ligamentous restraint averaged0.8±0.3Nm/° and was greater in positions where there were large slack regions. These dataprovide a target for restoration of normal capsular ligament tensions after joint preserving hipsurgery. Ligament repair is technically demanding, particularly for arthroscopic procedures,but failing to restore their function may increase the risk of osteoarthritic degeneration.
Stephen JM, Dodds AL, Lumpaopong P, et al., 2015, The Ability of Medial Patellofemoral Ligament Reconstruction to Correct Patellar Kinematics and Contact Mechanics in the Presence of a Lateralized Tibial Tubercle, AMERICAN JOURNAL OF SPORTS MEDICINE, Vol: 43, Pages: 2198-2207, ISSN: 0363-5465
- Author Web Link
- Cite
- Citations: 55
Kittl C, Schmeling A, Amis AA, 2015, The patellofemoral joint. Anatomy, biomechanics, and surgical interventions, ARTHROSKOPIE, Vol: 28, Pages: 172-180, ISSN: 0933-7946
- Author Web Link
- Cite
- Citations: 1
Tuncer M, Patel R, Cobb JP, et al., 2015, Variable bone mineral density reductions post-unicompartmental knee arthroplasty, KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY, Vol: 23, Pages: 2230-2236, ISSN: 0942-2056
- Author Web Link
- Cite
- Citations: 6
Halewood C, Traynor A, Bellemans J, et al., 2015, Anteroposterior Laxity After Bicruciate-Retaining Total Knee Arthroplasty Is Closer to the Native Knee Than ACL-Resecting TKA: A Biomechanical Cadaver Study., Journal of Arthroplasty, ISSN: 1532-8406
The purpose of this study was to examine whether a bicruciate retaining (BCR) TKA would yield anteroposterior (AP) laxity closer to the native knee than a posterior cruciate ligament retaining (CR) TKA. A BCR TKA was designed and compared to CR TKA and the native knee using cadaver specimens. AP laxity with the CR TKA was greater than the native knee (P=0.006) and BCR TKA (P=0.039), but no difference was found between the BCR TKA and the native knee. No significant differences were found in rotations between the prostheses and the native knee. BCR TKA was shown to be surgically feasible, reduced AP laxity versus CR TKA, and may improve knee stability without using conforming geometry in the implant design.
Wiik AV, Aqil A, Tankard S, et al., 2015, Downhill walking gait pattern discriminates between types of knee arthroplasty: improved physiological knee functionality in UKA versus TKA, KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY, Vol: 23, Pages: 1748-1755, ISSN: 0942-2056
- Author Web Link
- Open Access Link
- Cite
- Citations: 36
Ghosh KM, Hunt N, Blain A, et al., 2015, Isolated popliteus tendon injury does not lead to abnormal laxity in posterior-stabilised total knee arthroplasty, KNEE SURGERY SPORTS TRAUMATOLOGY ARTHROSCOPY, Vol: 23, Pages: 1763-1769, ISSN: 0942-2056
- Author Web Link
- Cite
- Citations: 14
Hansen UN, sukjamsri, amis, 2015, Digital volumecorrelationandmicro-CT:Anin-vitrotechniquefor measuringfull-field interfacemicromotionaroundpolyethyleneimplants, Journal of Biomechanics, ISSN: 1873-2380
Halewood C, Masouros S, Amis AA, 2015, Structure and function of the menisci, Meniscal Allograft Transplantation. A comprehensive review., Editors: Getgood, Spalding, Cole, Gersoff, Verdonk, ISBN: 978-0-9558873-5-2
Halewood C, Lumpaopong P, Stephen JM, et al., 2015, Functional Biomechanics with Cadaver Specimens, Experimental Research Methods in Orthopedics and Trauma, Editors: Simpson, Augat, Publisher: Thieme Medical Publishers, ISBN: 9783131731111
This book provides a comprehensive summary of all current research methodologies for translational and pre-clinical studies in biomechanics and orthopedic trauma surgery.
van Arkel RJ, Pal B, Darton H, et al., 2015, Biomechanics of Joints, Experimental Research Methods in Orthopedics and Trauma, Editors: Simpson, Augat, Publisher: Thieme Medical Publishers, ISBN: 9783131731111
This book provides a comprehensive summary of all current research methodologies for translational and pre-clinical studies in biomechanics and orthopedic trauma surgery.
Halewood C, Amis AA, 2015, Clinically relevant biomechanics of the knee capsule and ligaments, Knee Surgery, Sports Traumatology, Arthroscopy, Vol: 23, Pages: 2789-2796, ISSN: 0942-2056
The paper describes the concepts of primary and secondary restraints to knee joint stability and explains systematically how the tibia is stabilised against translational forces and rotational torques in different directions and axes, and how those vary across the arc of flexion–extension. It also shows how the menisci act to stabilise the knee, in addition to load carrying across the joint. It compares the properties of the natural stabilising structures with the strength and stiffness of autogenous tissue grafts and relates those strengths to the strength of graft fixation devices. A good understanding of the biomechanical behaviour of these various structures in the knee will help the surgeon in the assessment and treatment of single and multi-ligament injuries.
van Arkel RJ, Amis AA, Cobb JP, et al., 2015, The capsular ligaments provide more hip rotational restraint than the acetabular labrum and the ligamentum teres, Bone & Joint Journal, Vol: 97B, Pages: 484-491, ISSN: 2049-4394
In this in vitro study of the hip joint we examined which soft tissues act as primary and secondary passive rotational restraints when the hip joint is functionally loaded. A total of nine cadaveric left hips were mounted in a testing rig that allowed the application of forces, torques and rotations in all six degrees of freedom. The hip was rotated throughout a complete range of movement (ROM) and the contributions of the iliofemoral (medial and lateral arms), pubofemoral and ischiofemoral ligaments and the ligamentum teres to rotational restraint was determined by resecting a ligament and measuring the reduced torque required to achieve the same angular position as before resection. The contribution from the acetabular labrum was also measured. Each of the capsular ligaments acted as the primary hip rotation restraint somewhere within the complete ROM, and the ligamentum teres acted as a secondary restraint in high flexion, adduction and external rotation. The iliofemoral lateral arm and the ischiofemoral ligaments were primary restraints in two-thirds of the positions tested. Appreciation of the importance of these structures in preventing excessive hip rotation and subsequent impingement/instability may be relevant for surgeons undertaking both hip joint preserving surgery and hip arthroplasty.
Stephen JM, Halewood C, Kittl C, et al., 2015, The influence of posterior medial meniscocapsular lesions on tibiofemoral joint laxity in ACL deficient and reconstructed knees, British Association of Surgery of the Knee
Kawaguchi Y, Kondo E, Takeda R, et al., 2015, The role of fibers in the femoral attachment of the anterior cruciate ligament in resisting tibial displacement, ARTHROSCOPY-THE JOURNAL OF ARTHROSCOPIC AND RELATED SURGERY, Vol: 31, Pages: 435-444, ISSN: 0749-8063
PurposeThe purpose was to clarify the load-bearing functions of the fibers of the femoral anterior cruciate ligament (ACL) attachment in resisting tibial anterior drawer and rotation.MethodsA sequential cutting study was performed on 8 fresh-frozen human knees. The femoral attachment of the ACL was divided into a central area that had dense fibers inserting directly into the femur and anterior and posterior fan-like extension areas. The ACL fibers were cut sequentially from the bone: the posterior fan-like area in 2 stages, the central dense area in 4 stages, and then the anterior fan-like area in 2 stages. Each knee was mounted in a robotic joint testing system that applied tibial anteroposterior 6-mm translations and 10° or 15° of internal rotation at 0° to 90° of flexion. The reduction of restraining force or moment was measured after each cut.ResultsThe central area resisted 82% to 90% of the anterior drawer force; the anterior fan-like area, 2% to 3%; and the posterior fan-like area, 11% to 15%. Among the 4 central areas, most load was carried close to the roof of the intercondylar notch: the anteromedial bundle resisted 66% to 84% of the force and the posterolateral bundle resisted 16% to 9% from 0° to 90° of flexion. There was no clear pattern for tibial internal rotation, with the load shared among the posterodistal and central areas near extension and mostly the central areas in flexion.ConclusionsUnder the experimental conditions described, 66% to 84% of the resistance to tibial anterior drawer arose from the ACL fibers at the central-proximal area of the femoral attachment, corresponding to the anteromedial bundle; the fan-like extension fibers contributed very little. This work did not support moving a single-bundle ACL graft to the side wall of the notch or attempting to cover the whole attachment area if the intention was to mimic how the natural ACL resists tibial displacements.Clinical RelevanceThere is ongoing debate about ho
Kittl C, Halewood C, Stephen JM, et al., 2015, Length change patterns in the lateral extra-articular structures of the knee and related reconstructions, American Journal of Sports Medicine, Vol: 43, Pages: 354-362, ISSN: 0363-5465
Background:Lateral extra-articular soft tissue reconstructions in the knee may be used as a combined procedure in revision anterior cruciate ligament surgery as well as in primary treatment for patients who demonstrate excessive anterolateral rotatory instability. Only a few studies examining length change patterns and isometry in lateral extra-articular reconstructions have been published.Purpose:To determine a recommended femoral insertion area and graft path for lateral extra-articular reconstructions by measuring length change patterns through a range of knee flexion angles of several combinations of tibial and femoral insertion points on the lateral side of the knee.Study Design:Controlled laboratory study.Methods:Eight fresh-frozen cadaveric knees were freed of skin and subcutaneous fat. The knee was then mounted in a kinematics rig that loaded the quadriceps muscles and simulated open-chain knee flexion. The length changes of several combinations of tibiofemoral points were measured at knee flexion angles between 0° and 90° by use of linear variable displacement transducers. The changes in length relative to the 0° measurement were recorded.Results:The anterior fiber region of the iliotibial tract displayed a significantly different (P < .001) length change pattern compared with the posterior fiber region. The reconstructions that had a femoral insertion site located proximal to the lateral epicondyle and with the grafts passed deep to the lateral collateral ligament displayed similar length change patterns to each other, with small length increases during knee extension. These reconstructions also showed a significantly lower total strain range compared with the reconstruction located anterior to the epicondyle (P < .001).Conclusion:These findings show that the selection of graft attachment points and graft course affects length change pattern during knee flexion. A graft attached proximal to the lateral femoral epicondyle and running deep
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.