Publications by authors named "Andy Williams"

60 Publications

Prioritised challenges in the management of acute knee dislocations are stiffness, obesity, treatment delays and associated limb-threatening injuries: a global consensus study.

J ISAKOS 2021 Jul 5;6(4):193-198. Epub 2021 Mar 5.

University of Texas McGovern Medical School, Pittsburgh, Pennsylvania, USA.

Objectives: Heterogeneous patient factors and injury mechanisms result in a great variety of injury patterns encountered in knee dislocations (KD). Attempts to improve outcome can focus on a wide range of challenges. The aim of this study was to establish and prioritise a list of challenges encountered when treating patients with acute KD.

Methods: A modified Delphi consensus study was conducted with international knee specialists who generated a prioritised list of challenges. Selected priorities were limited to half of the possible items. Agreement of more than 70% was defined as consensus on each of these items a priori.

Results: Ninety-one international surgeons participated in the first round. The majority worked in public hospitals and treated patients from low-income and middle-income households. Their propositions were prioritised by 27 knee surgeons from Europe, Africa, Asia, as well as North and South America, with a mean of 15.3 years of experience in knee surgery (SD 17.8). Consensus was reached for postoperative stiffness, obesity, delay to presentation and associated common peroneal nerve injuries. Challenges such as vascular injuries, ipsilateral fractures, open injuries as well as residual laxity were also rated high. Most of these topics with high priority are key during the initial management of a patient with KD, at presentation. Topics with lower priority were postsurgical challenges, such as patient insight, expectations and compliance, rehabilitation programme, and pain management.

Conclusion: This consensus study has a wide geographical footprint of experts around the world practising in various settings. These participants prioritised stiffness, obesity, treatment delays and associated limb-threatening injuries as the most important challenges when managing a patient with acute KD. This list calls for applicable and feasible solutions for these challenges in a global setting. It should be used to prioritise research efforts and discuss treatment guidelines.

Level Of Evidence: V.
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http://dx.doi.org/10.1136/jisakos-2020-000565DOI Listing
July 2021

Knee Joint Line Obliquity Causes Tibiofemoral Subluxation That Alters Contact Areas and Meniscal Loading.

Am J Sports Med 2021 Jul 14;49(9):2351-2360. Epub 2021 Jun 14.

The Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, UK.

Background: Little scientific evidence is available regarding the effect of knee joint line obliquity (JLO) before and after coronal realignment osteotomy.

Hypotheses: Higher JLO would lead to abnormal relative position of the femur on the tibia, a shift of the joint contact areas, and elevated joint contact pressures.

Study Design: Descriptive laboratory study.

Methods: 10 fresh-frozen human cadaveric knees (age, 59 ± 5 years) were axially loaded to 1500 N in a materials testing machine with the joint line tilted 0°, 4°, 8°, and 12° varus ("downhill" medially) and valgus, at 0° and 20° of knee flexion. The mechanical compression axis was aligned to the center of the tibial plateau. Contact pressure and contact area were recorded by pressure sensors inserted between the tibia and femur below the menisci. Changes in relative femoral and tibial position in the coronal plane were obtained by an optical tracking system.

Results: Both medial and lateral JLO caused significant tibiofemoral subluxation and pressure distribution changes. Medial (varus) JLO caused the femur to subluxate medially down the coronal slope of the tibial plateau, and vice versa for lateral (valgus) downslopes ( < .01), giving a 6-mm range of subluxation. The areas of peak pressure moved 12 mm and 8 mm across the medial and lateral condyles, onto the downhill meniscus and the "uphill" tibial spine. Changes in JLO had only small effects on maximum contact pressures.

Conclusion: A 4° change of JLO during load bearing caused significant mediolateral tibiofemoral subluxation. The femur slid down the slope of the tibial plateau to abut the tibial eminence and also to rest on the downhill meniscus. This caused large movements of the tibiofemoral contact pressures across each compartment.

Clinical Relevance: These results provide important information for understanding the consequences of creating coronal JLO and for clinical practice in terms of osteotomy planning regarding the effect on JLO. This information provides guidance regarding the choice of single- or double-level osteotomy. Excessive JLO alteration may cause abnormal tibiofemoral joint articulation and chondral or meniscal loading.
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http://dx.doi.org/10.1177/03635465211020478DOI Listing
July 2021

An Anterior Cruciate Ligament In Vitro Rupture Model Based on Clinical Imaging.

Am J Sports Med 2021 Jul 11;49(9):2387-2395. Epub 2021 Jun 11.

Biomechanics Group, Mechanical Engineering Department, Imperial College London, London, UK.

Background: Biomechanical studies on anterior cruciate ligament (ACL) injuries and reconstructions are based on ACL transection instead of realistic injury trauma.

Purpose: To replicate an ACL injury in vitro and compare the laxity that occurs with that after an isolated ACL transection injury before and after ACL reconstruction.

Study Design: Controlled laboratory study.

Methods: Nine paired knees were ACL injured or ACL transected. For ACL injury, knees were mounted in a rig that imposed tibial anterior translation at 1000 mm/min to rupture the ACL at 22.5° of flexion, 5° of internal rotation, and 710 N of joint compressive force, replicating data published on clinical bone bruise locations. In contralateral knees, the ACL was transected arthroscopically at midsubstance. Both groups had ACL reconstruction with bone-patellar tendon-bone graft. Native, ACL-deficient, and reconstructed knee laxities were measured in a kinematics rig from 0° to 100° of flexion with optical tracking: anterior tibial translation (ATT), internal rotation (IR), anterolateral (ATT + IR), and pivot shift (IR + valgus).

Results: The ACL ruptured at 26 ± 5 mm of ATT and 1550 ± 620 N of force (mean ± SD) with an audible spring-back tibiofemoral impact with 5 of valgus. ACL injury and transection increased ATT ( < .001). ACL injury caused greater ATT than ACL transection by 1.4 mm (range, 0.4-2.2 mm; = .033). IR increased significantly in ACL-injured knees between 0° and 30° of flexion and in ACL transection knees from 0° to 20° of flexion. ATT during the ATT + IR maneuver was increased by ACL injury between 0° and 80° and after ACL transection between 0° and 60°. Residual laxity persisted after ACL reconstruction from 0° to 40° after ACL injury and from 0° to 20° in the ACL transection knees. ACL deficiency increased ATT and IR in the pivot-shift test ( < .001). The ATT in the pivot-shift increased significantly at 0° to 20° after ACL transection and 0° to 50° after ACL injury, and this persisted across 0° to 20° and 0° to 40° after ACL reconstruction.

Conclusion: This study developed an ACL injury model in vitro that replicated clinical ACL injury as evidenced by bone bruise patterns. ACL injury caused larger increases of laxity than ACL transection, likely because of damage to adjacent tissues; these differences often persisted after ACL reconstruction.

Clinical Relevance: This in vitro model created more realistic ACL injuries than surgical transection, facilitating future evaluation of ACL reconstruction techniques.
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http://dx.doi.org/10.1177/03635465211017145DOI Listing
July 2021

Anterolateral complex injuries occur in the majority of 'isolated' anterior cruciate ligament ruptures.

Knee Surg Sports Traumatol Arthrosc 2021 Apr 1. Epub 2021 Apr 1.

Fortius Clinic, 17 Fitzhardinge St, London, W1H 6EQ, UK.

Purpose: The anterolateral soft tissue envelope of the knee is frequently injured at the time of ACL rupture. This study aims to investigate the MRI injury patterns to the Anterolateral complex and their associations in patients with acute 'isolated ligament' ACL ruptures.

Methods: Professional athletes who underwent ACL reconstruction for complete ACL rupture between 2015 and 2019 were included in this study. Patients' characteristics and intraoperative findings were retrieved from clinical and surgical documentation. Preoperative MRIs were evaluated and the injuries to respective structures of the Anterolateral complex and their associations were recorded.

Results: Anterolateral complex injuries were noted in 63% of cases. The majority of injuries were to Kaplan Fibre (39% isolated injury and 19% combined with Anterolateral ligament injury). There was a very low incidence of isolated Anterolateral ligament injuries (2%). Kaplan Fibre injuries are associated with the presence of lateral femoral condyle bone oedema, and injuries to the superficial MCL, deep MCL, and ramp lesions. High grade pivot shift test was not associated with the presence of Kaplan Fibre or Anterolateral ligament injuries. Patients with an intact Anterolateral complex sustained injury to other knee structures (13% to medial ligament complex, 14% to medial meniscus, and 16% to lateral meniscus).

Conclusion: There is a high incidence of concomitant Anterolateral complex injuries in combination with ACL ruptures, with Kaplan Fibre (and therefore the deep capsulo-osseous layer of the iliotibial band) being the most commonly injured structure. Anterolateral ligament injuries occur much less frequently. These findings reinforce the importance of considering the presence of, and if necessary, treating injuries to structures other than the ACL, as a truly isolated ACL injury is rare.
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http://dx.doi.org/10.1007/s00167-021-06543-6DOI Listing
April 2021

High incidence of superficial and deep medial collateral ligament injuries in 'isolated' anterior cruciate ligament ruptures: a long overlooked injury.

Knee Surg Sports Traumatol Arthrosc 2021 Mar 4. Epub 2021 Mar 4.

Fortius Clinic, 17 Fitzhardinge St, London, W1H 6EQ, UK.

Purpose: In anterior cruciate ligament (ACL) injuries, concomitant damage to peripheral soft tissues is associated with increased rotatory instability of the knee. The purpose of this study was to investigate the incidence and patterns of medial collateral ligament complex injuries in patients with clinically 'isolated' ACL ruptures.

Methods: Patients who underwent ACL reconstruction for complete 'presumed isolated' ACL rupture between 2015 and 2019 were retrospectively included in this study. Patient's characteristics and intraoperative findings were retrieved from clinical and surgical documentation. Preoperative MRIs were evaluated and the grade and location of injuries to the superficial MCL (sMCL), dMCL and the posterior oblique ligament (POL) recorded. All patients were clinically assessed under anaesthesia with standard ligament laxity tests.

Results: Hundred patients with a mean age of 22.3 ± 4.9 years were included. The incidence of concomitant MCL complex injuries was 67%. sMCL injuries occurred in 62%, dMCL in 31% and POL in 11% with various injury patterns. A dMCL injury was significantly associated with MRI grade II sMCL injuries, medial meniscus 'ramp' lesions seen at surgery and bone oedema at the medial femoral condyle (MFC) adjacent to the dMCL attachment site (p < 0.01). Logistic regression analysis identified younger age (OR 1.2, p < 0.05), simultaneous sMCL injury (OR 6.75, p < 0.01) and the presence of bone oedema at the MFC adjacent to the dMCL attachment site (OR 5.54, p < 0.01) as predictive factors for a dMCL injury.

Conclusion: The incidence of combined ACL and medial ligament complex injuries is high. Lesions of the dMCL were associated with ramp lesions, MFC bone oedema close to the dMCL attachment, and sMCL injury. Missed AMRI is a risk factor for ACL graft failure from overload and, hence, oedema in the MCL (especially dMCL) demands careful assessment for AMRI, even in the knee lacking excess valgus laxity. This study provides information about specific MCL injury patterns including the dMCL in ACL ruptures and will allow surgeons to initiate individualised treatment.

Level Of Evidence: III.
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http://dx.doi.org/10.1007/s00167-021-06514-xDOI Listing
March 2021

Safe Femoral Fixation Depth and Orientation for Lateral Extra-Articular Tenodesis in Anterior Cruciate Ligament Reconstruction.

Orthop J Sports Med 2021 Jan 29;9(1):2325967120976591. Epub 2021 Jan 29.

Fortius Clinic, London, UK.

Background: Patients who undergo anterior cruciate ligament (ACL) reconstruction (ACLR) can have a persistent postoperative pivot shift. Performing lateral extra-articular tenodesis (LET) concurrently has been proposed to address this; however, LET femoral fixation may interfere with the ACLR femoral tunnel, which could damage the ACL graft or its fixation.

Purpose: To evaluate the safe maximum implant or tunnel depth for a modified Lemaire LET when combined with ACLR anteromedial portal femoral tunnel drilling and to validate the safe LET drilling angles to avoid conflict with the ACLR femoral tunnel.

Study Design: Descriptive laboratory study.

Methods: Twelve fresh-frozen cadaveric knees were used. With each knee at 120° of flexion, an ACLR femoral tunnel in the anteromedial bundle position was created arthroscopically via the anteromedial portal using a 5-mm offset guide, a guide wire, and an 8-mm reamer, which was left in situ. A modified Lemaire LET was performed using a 1 cm-wide iliotibial band strip harvested with the distal attachment intact, to be fixed in the femur. The desired LET fixation point was identified with an external aperture 10 mm proximal and 5 mm posterior to the fibular collateral ligament's femoral attachment, and a 2.4-mm guide wire was drilled, aiming at 0°, 10°, 20°, or 30° anteriorly in the axial plane and at 0°, 10°, or 20° proximally in the coronal plane (12 different drilling angle combinations). The relationship between the LET drilling guide wire and the ACLR femoral tunnel reamer was recorded for each combination. When a collision with the femoral tunnel was recorded, the LET wire depth was measured.

Results: Collision with the ACLR femoral tunnel occurred at a mean LET wire depth of 23.6 mm (range, 15-33 mm). No correlation existed between LET wire depth and LET drilling orientation ( = 0.066; = .67). Drilling angle in the axial plane was significantly associated with the occurrence of tunnel conflict ( < .001). However, no such association was detected when comparing the drilling angle in the coronal plane ( = .267).

Conclusion: Conflict of LET femoral fixation with the ACLR femoral tunnel using anteromedial portal drilling occurred at a mean depth of 23.6 mm but also at a depth as little as 15 mm, which is shorter than most implants. When longer implants or tunnels are used, the orientation should be directed at least 30° anteriorly in the axial plane to minimize the risk of tunnel conflict, bearing in mind the risk of joint violation.

Clinical Relevance: This study provides important information for surgeons performing LET in combination with ACLR anteromedial portal femoral tunnel drilling regarding safe femoral implant or tunnel length and orientation.
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http://dx.doi.org/10.1177/2325967120976591DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7869183PMC
January 2021

A Validated, Automated, 3-Dimensional Method to Reliably Measure Tibial Torsion.

Am J Sports Med 2021 03 3;49(3):747-756. Epub 2021 Feb 3.

Department of Mechanical Engineering, Imperial College London, London, UK.

Background: Tibial torsion is a twist in the tibia measured as an angle between a proximal axis line and a distal axis line. Abnormal torsion has been associated with a variety of painful clinical syndromes of the lower limb. Measurements of normal tibial torsion reported by different authors vary by 100% (ranging from 20° to 42°), making it impossible to determine normal and pathological levels.

Purpose: To address the problem of unreliable measurements, this study was conducted to define an automated, validated computer method to calculate tibial torsion. Reliability was compared with current clinical methods. The difference between measurements of torsion generated from computed tomography (CT) and magnetic resonance imaging (MRI) scans of the same bone, and between males and females, was assessed.

Study Design: Controlled laboratory study.

Methods: Previous methods of analyzing tibial torsion were reviewed, and limitations were identified. An automated measurement method to address these limitations was defined. A total of 56 cadaveric and patient tibiae (mean ± SD age, 37 ± 15 years; range, 17-71 years; 28 female) underwent CT scanning, and 3 blinded assessors made torsion measurements by applying 2 current clinical methods and the automated method defined in the present article. Intraclass correlation coefficient (ICC) values were calculated. Further, 12 cadaveric tibiae were scanned by MRI, stripped of tissue, and measured using a structured light (SL) scanner. Differences between torsion values obtained from CT, SL, and MRI scans, and between males and females, were compared using tests. SPSS was used for all statistical analysis.

Results: When the automated method was used, the tibiae had a mean external torsion of 29°± 11° (range, 9°-65). Automated torsion assessment had excellent reliability (ICC, 1), whereas current methods had good reliability (ICC, 0.78-0.81). No significant difference was found between the torsion values calculated from SL and CT ( = .802), SL and MRI ( = .708), or MRI and CT scans ( = .826).

Conclusion: The use of software to automatically perform measurements ensures consistency, time efficiency, validity, and accuracy not possible with manual measurements, which are dependent on assessor experience.

Clinical Relevance: We recommend that this method be adopted in clinical practice to establish databases of normal and pathological tibial torsion reference values and ultimately guide management of related conditions.
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http://dx.doi.org/10.1177/0363546520986873DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7917570PMC
March 2021

Developing a whole-school mental health and wellbeing intervention through pragmatic formative process evaluation: a case-study of innovative local practice within The School Health Research network.

BMC Public Health 2021 01 18;21(1):154. Epub 2021 Jan 18.

School of Social Sciences, Cardiff University, Cardiff, UK.

Background: The evidence-base for whole school approaches aimed at improving student mental health and wellbeing remains limited. This may be due to a focus on developing and evaluating de-novo, research-led interventions, while neglecting the potential of local, contextually-relevant innovation that has demonstrated acceptability and feasibility. This study reports a novel approach to modelling and refining the programme theory of a whole-school restorative approach, alongside plans to scale up through a national educational infrastructure in order to support robust scientific evaluation.

Methods: A pragmatic formative process evaluation was conducted of a routinized whole-school restorative approach aimed at improving student mental health and wellbeing in Wales.

Results: The study reports the six phases of the pragmatic formative process evaluation. These are: 1) identification of innovative local practice; 2) scoping review of evidence-base to identify potential programme theory; outcomes; and contextual characteristics that influence implementation; 3) establishment of a Transdisciplinary Action Research (TDAR) group; 4) co-production and confirmation of an initial programme theory with stakeholders; 5) planning to optimise intervention delivery in local contexts; and 6) planning for feasibility and outcome evaluation. The phases of this model may be iterative and not necessarily sequential.

Conclusions: Formative, pragmatic process evaluations can support researchers, policy-makers and practitioners in developing robust scientific evidence-bases for acceptable and feasible local innovations that do not already have a clear evidence base. The case of a whole-school restorative approach provides a case example of how such an evaluation may be undertaken.
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http://dx.doi.org/10.1186/s12889-020-10124-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7814700PMC
January 2021

Single-Stage Revision Anterior Cruciate Ligament Reconstruction: Experience With 91 Patients (40 Elite Athletes) Using an Algorithm.

Am J Sports Med 2021 02 17;49(2):364-373. Epub 2020 Dec 17.

Fortius Clinic, London, UK.

Background: The increased prevalence of anterior cruciate ligament (ACL) reconstruction has led to an increased need for revision ACL reconstructions. Despite the growing body of literature indicating that single-stage revision ACL reconstruction can yield good outcomes, there is a lack of data for determining when and how to safely perform a single-stage revision.

Purpose: To assess the outcomes, graft failure rates, and return-to-play rates of a decision-making algorithm for single-stage revision ACL reconstruction.

Study Design: Case series; Level of evidence, 4.

Methods: We reviewed a consecutive series of revision ACL reconstructions performed by the senior author between September 2009 and July 2016 with minimum 2-year follow-up. All patients were assessed, and decision making was undertaken according to the algorithm. Outcomes measured were further surgery, graft rerupture, re-revision, Tegner score, and Knee injury and Osteoarthritis Outcome Score (KOOS). For the elite athlete population, return-to-play time, duration, and level of play after surgery as compared with preinjury were also determined.

Results: During this period, 93 procedures were performed in 92 patients (40 elite athletes). Two 2-stage procedures were undertaken, leaving 91 single-stage procedures (91 patients) to form the basis for further study. At a mean 4.3 years (SD, 2.2 years) after surgery, there had been 2 re-revisions (2.2%) and 2 further instances of graft failure that had not been re-revised (total graft failure rate, 4.4%). There were 17 subsequent procedures, including 6 arthroscopic partial meniscectomies, 5 removals of prominent implants, and 1 total knee arthroplasty. The mean Tegner score was 8.02 before graft rerupture and 7.1 at follow-up. At follow-up, the mean KOOS outcomes were 79.3 for Symptoms, 88.0 for Pain, 94.2 for Activities of Daily Living, 73.6 for Sport, and 68.9 for Quality of Life. Of 40 elite athletes, 35 returned to play at a mean 11.2 months (SD, 3.6 months) after surgery.

Conclusion: Single-stage revision ACL reconstructions can be performed reliably in the majority of patients, with good clinical outcomes, low rerupture rates, and high-return-to play rates, even in the elite athlete population.
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http://dx.doi.org/10.1177/0363546520976633DOI Listing
February 2021

Comparative accuracy of lower limb bone geometry determined using MRI, CT, and direct bone 3D models.

J Orthop Res 2020 Nov 22. Epub 2020 Nov 22.

Department of Mechanical Engineering, Imperial College London, London, UK.

Advancements in imaging and segmentation techniques mean that three dimensional (3D) modeling of bones is now increasingly used for preoperative planning and registration purposes. Computer tomography (CT) scans are commonly used due to their high bone-soft tissue contrast, however they expose subjects to radiation. Alternatively, magnetic resonance imaging (MRI) is radiation-free: however, geometric field distortion and poor bone contrast have been reported to degrade bone model validity compared to CT. The present study assessed the accuracy of 3D femur and tibia models created from "Black Bone" 3T MRI and high resolution CT scans taken from 12 intact cadaveric lower limbs by comparing them with scans of the de-fleshed and cleaned bones carried out using a high-resolution portable compact desktop 3D scanner (Model HDI COMPACT C210; Polyga). This scanner used structured light (SL) to capture 3D scans with an accuracy of up to 35 μm. Image segmentation created 3D models and for each bone the corresponding CT and MRI models were aligned with the SL model using the iterative closest point (ICP) algorithm and the differences between models calculated. Hausdorff distance was also determined. Compared to SL scans, the CT models had an ICP error of 0.82 ± 0.2 and 0.85 ± 0.2 mm for the tibia and femur respectively, whilst the MRI models had an error of 0.97 ± 0.2 and 0.98 ± 0.18 mm. A one-way analysis of variance found no significant difference in the Hausdorff distances or ICP values between the three scanning methods (p > .05). The black bone MRI method can provide accurate geometric measures of the femur and tibia that are comparable to those achieved with CT. Given the lack of ionizing radiation this has significant benefits for clinical populations and also potential for application in research settings.
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http://dx.doi.org/10.1002/jor.24923DOI Listing
November 2020

The medial collateral ligament: the neglected ligament.

Knee Surg Sports Traumatol Arthrosc 2020 12 12;28(12):3698-3699. Epub 2020 Jul 12.

Biomechanics Group, Mechanical Engineering Department, Imperial College London, London, SW7 2AZ, UK.

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http://dx.doi.org/10.1007/s00167-020-06116-zDOI Listing
December 2020

Length-change patterns of the medial collateral ligament and posterior oblique ligament in relation to their function and surgery.

Knee Surg Sports Traumatol Arthrosc 2020 Dec 1;28(12):3720-3732. Epub 2020 Jun 1.

The Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK.

Purpose: To define the length-change patterns of the superficial medial collateral ligament (sMCL), deep MCL (dMCL), and posterior oblique ligament (POL) across knee flexion and with applied anterior and rotational loads, and to relate these findings to their functions in knee stability and to surgical repair or reconstruction.

Methods: Ten cadaveric knees were mounted in a kinematics rig with loaded quadriceps, ITB, and hamstrings. Length changes of the anterior and posterior fibres of the sMCL, dMCL, and POL were recorded from 0° to 100° flexion by use of a linear displacement transducer and normalised to lengths at 0° flexion. Measurements were repeated with no external load, 90 N anterior draw force, and 5 Nm internal and 5 Nm external rotation torque applied.

Results: The anterior sMCL lengthened with flexion (p < 0.01) and further lengthened by external rotation (p < 0.001). The posterior sMCL slackened with flexion (p < 0.001), but was lengthened by internal rotation (p < 0.05). External rotation lengthened the anterior dMCL fibres by 10% throughout flexion (p < 0.001). sMCL release allowed the dMCL to become taut with valgus rotation (p < 0.001). The anterior and posterior POL fibres slackened with flexion (p < 0.001), but were elongated by internal rotation (p < 0.001).

Conclusion: The structures of the medial ligament complex react differently to knee flexion and applied loads. Structures attaching posterior to the medial epicondyle are taut in extension, whereas the anterior sMCL, attaching anterior to the epicondyle, is tensioned during flexion. The anterior dMCL is elongated by external rotation. These data offer the basis for MCL repair and reconstruction techniques regarding graft positioning and tensioning.
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http://dx.doi.org/10.1007/s00167-020-06050-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7669796PMC
December 2020

Redesigning Metal Interference Screws Can Improve Ease of Insertion While Maintaining Fixation of Soft-Tissue Anterior Cruciate Ligament Reconstruction Grafts.

Arthrosc Sports Med Rehabil 2020 Apr 6;2(2):e137-e144. Epub 2020 Apr 6.

Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, England.

Purpose: To compare the fixation strength and loads on insertion of a titanium alloy interference screw with a modified tip against a conventional titanium interference screw.

Methods: Slippage of bovine digital extensor tendons (as substitutes for human tendon grafts) under cyclic loading and interference fixation strength under a pullout test were recorded in 10 cadaveric knees, with 2 tunnels drilled in each femur and tibia to provide pair-wise comparisons between the modified-tip screw (MS) and conventional screw (CS). To analyze screw insertion, 10 surgeons blindly inserted pairs of the MS and CS into bone-substitute blocks (with polyester shoelaces as graft substitutes), with insertion loads measured using a force/torque sensor.

Results: No differences were found between the MS and CS either in graft slippage from the femur ( = .661) or tibia ( = .950) or in ultimate load to failure from the femur ( = .952) or tibia ( = .126). On insertion, the MS required less axial force application (78 ± 38 N,  = .001) and fewer attempted turns (2 ± 1, < .001) to engage with the bone tunnel than the CS (99 ± 43 N and 4 ± 4, respectively). In 90% of the paired insertion tests, the screw identified by the surgeon as being easier to initially insert was the MS.

Conclusions: The MS was found to be easier to engage with the bone tunnel and initially insert than the CS while still achieving similar immediate postsurgical fixation strength.

Clinical Relevance: The study shows that screw designs can be improved to ease insertion into a bone tunnel, which should reduce any likelihood of ligament reconstruction graft damage.
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http://dx.doi.org/10.1016/j.asmr.2020.01.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7190538PMC
April 2020

Fast Bowler's knee - anteromedial articular impingement.

J Exp Orthop 2020 Apr 8;7(1):20. Epub 2020 Apr 8.

Fortius Clinic, 17 Fitzhardinge Street, London, W1H 6EQ, UK.

Purpose: To describe a series of impingement lesions found on the anterior aspect of the medial femoral condyle in international cricketers.

Methods: Seven international level fast bowlers presented to our clinic with knee pain in the lead leg between 2005 and 2013. The mean age of the patients was 26.7 years (20-29 years). In all patients a careful history and examination was undertaken followed by appropriate investigations. Conservative management and arthroscopic surgery were performed on these cases. We aimed for a pain free quiet knee with resolved oedema on MRI and return to sport.

Results: MRI images showed oedema in the medial femoral condyle in all patients and 4 patients also had associated cartilage loss. These 4 patients underwent arthroscopic surgery whereas the other 3 were less symptomatic and were managed conservatively. All patients returned to international cricket at an average of 6 months in the non-operative group and 8 months in the operative group.

Conclusion: Anterior impingement of the anteromedial femoral condyle can be a potentially serious lesion in the fast bowler. A strong index of suspicion regarding this lesion has to be exercised when a fast bowler attends with knee pain and effusion.
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http://dx.doi.org/10.1186/s40634-020-00237-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7142198PMC
April 2020

Ethnically diverse urban transmission networks of without evidence of HIV serosorting.

Sex Transm Infect 2020 03 29;96(2):106-109. Epub 2019 Oct 29.

Nuffield Department of Medicine, University of Oxford, Oxford, UK

Objective: We aimed to characterise gonorrhoea transmission patterns in a diverse urban population by linking genomic, epidemiological and antimicrobial susceptibility data.

Methods: isolates from patients attending sexual health clinics at Barts Health NHS Trust, London, UK, during an 11-month period underwent whole-genome sequencing and antimicrobial susceptibility testing. We combined laboratory and patient data to investigate the transmission network structure.

Results: One hundred and fifty-eight isolates from 158 patients were available with associated descriptive data. One hundred and twenty-nine (82%) patients identified as male and 25 (16%) as female; four (3%) records lacked gender information. Self-described ethnicities were: 51 (32%) English/Welsh/Scottish; 33 (21%) white, other; 23 (15%) black British/black African/black, other; 12 (8%) Caribbean; 9 (6%) South Asian; 6 (4%) mixed ethnicity; and 10 (6%) other; data were missing for 14 (9%). Self-reported sexual orientations were 82 (52%) men who have sex with men (MSM); 49 (31%) heterosexual; 2 (1%) bisexual; data were missing for 25 individuals. Twenty-two (14%) patients were HIV positive. Whole-genome sequence data were generated for 151 isolates, which linked 75 (50%) patients to at least one other case. Using sequencing data, we found no evidence of transmission networks related to specific ethnic groups (p=0.64) or of HIV serosorting (p=0.35). Of 82 MSM/bisexual patients with sequencing data, 45 (55%) belonged to clusters of ≥2 cases, compared with 16/44 (36%) heterosexuals with sequencing data (p=0.06).

Conclusion: We demonstrate links between 50% of patients in transmission networks using a relatively small sample in a large cosmopolitan city. We found no evidence of HIV serosorting. Our results do not support assortative selectivity as an explanation for differences in gonorrhoea incidence between ethnic groups.
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http://dx.doi.org/10.1136/sextrans-2019-054025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7035678PMC
March 2020

Biomechanical Assessment of a Distally Fixed Lateral Extra-articular Augmentation Procedure in the Treatment of Anterolateral Rotational Laxity of the Knee.

Am J Sports Med 2019 07 24;47(9):2102-2109. Epub 2019 Jun 24.

OrthoSport Victoria, Epworth Healthcare, Melbourne, Australia.

Background: Most lateral extra-articular tenodesis (LET) procedures rely on passing a strip of the iliotibial band (ITB) under the fibular (lateral) collateral ligament and fixing it proximally to the femur. The Ellison procedure is a distally fixed lateral extra-articular augmentation procedure with no proximal fixation of the ITB. It has the potential advantages of maintaining a dynamic element of control of knee rotation and avoiding the possibility of overconstraint.

Hypothesis: The modified Ellison procedure would restore native knee kinematics after sectioning of the anterolateral capsule, and closure of the ITB defect would decrease rotational laxity of the knee.

Study Design: Controlled laboratory study.

Methods: Twelve fresh-frozen cadaveric knees were tested in a 6 degrees of freedom robotic system through 0° to 90° of knee flexion to assess anteroposterior, internal rotation (IR), and external rotation laxities. A simulated pivot shift (SPS) was performed at 0°, 15°, 30°, and 45° of flexion. Kinematic testing was performed in the intact knee and anterolateral capsule-injured knee and after the modified Ellison procedure, with and without closure of the ITB defect. A novel pulley system was used to load the ITB at 30 N for all testing states. Statistical analysis used repeated measures analyses of variance and paired tests with Bonferroni adjustments.

Results: Sectioning of the anterolateral capsule increased anterior drawer and IR during isolated displacement and with the SPS (mean increase, 2° of IR; < .05). The modified Ellison procedure reduced both isolated and coupled IR as compared with the sectioned state ( < .05). During isolated testing, IR was reduced close to that of the intact state with the modified Ellison procedure, except at 30° of knee flexion, when it was slightly overconstrained. During the SPS, IR with the closed modified Ellison was less than that in the intact state at 15° and 30° of flexion. No significant differences in knee kinematics were seen between the ITB defect open and closed.

Conclusion: A distally fixed lateral augmentation procedure can closely restore knee laxities to native values in an anterolateral capsule-sectioned knee. Although the modified Ellison did result in overconstraint to isolated IR and coupled IR during SPS, this occurred only in the early range of knee flexion. Closure of the ITB defect had no effect on knee kinematics.

Clinical Relevance: A distally fixed lateral extra-articular augmentation procedure provides an alternative to a proximally fixed LET and can reduce anterolateral laxity in the anterolateral capsule-injured knee and restore kinematics close to the intact state.
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http://dx.doi.org/10.1177/0363546519856331DOI Listing
July 2019

Claims of causality in health news: a randomised trial.

BMC Med 2019 05 16;17(1):91. Epub 2019 May 16.

School of Psychology, Cardiff University, Cardiff, UK.

Background: Misleading news claims can be detrimental to public health. We aimed to improve the alignment between causal claims and evidence, without losing news interest (counter to assumptions that news is not interested in communicating caution).

Methods: We tested two interventions in press releases, which are the main sources for science and health news: (a) aligning the headlines and main causal claims with the underlying evidence (strong for experimental, cautious for correlational) and (b) inserting explicit statements/caveats about inferring causality. The 'participants' were press releases on health-related topics (N = 312; control = 89, claim alignment = 64, causality statement = 79, both = 80) from nine press offices (journals, universities, funders). Outcomes were news content (headlines, causal claims, caveats) in English-language international and national media (newspapers, websites, broadcast; N = 2257), news uptake (% press releases gaining news coverage) and feasibility (% press releases implementing cautious statements).

Results: News headlines showed better alignment to evidence when press releases were aligned (intention-to-treat analysis (ITT) 56% vs 52%, OR = 1.2 to 1.9; as-treated analysis (AT) 60% vs 32%, OR = 1.3 to 4.4). News claims also followed press releases, significant only for AT (ITT 62% vs 60%, OR = 0.7 to 1.6; AT, 67% vs 39%, OR = 1.4 to 5.7). The same was true for causality statements/caveats (ITT 15% vs 10%, OR = 0.9 to 2.6; AT 20% vs 0%, OR 16 to 156). There was no evidence of lost news uptake for press releases with aligned headlines and claims (ITT 55% vs 55%, OR = 0.7 to 1.3, AT 58% vs 60%, OR = 0.7 to 1.7), or causality statements/caveats (ITT 53% vs 56%, OR = 0.8 to 1.0, AT 66% vs 52%, OR = 1.3 to 2.7). Feasibility was demonstrated by a spontaneous increase in cautious headlines, claims and caveats in press releases compared to the pre-trial period (OR = 1.01 to 2.6, 1.3 to 3.4, 1.1 to 26, respectively).

Conclusions: News claims-even headlines-can become better aligned with evidence. Cautious claims and explicit caveats about correlational findings may penetrate into news without harming news interest. Findings from AT analysis are correlational and may not imply cause, although here the linking mechanism between press releases and news is known. ITT analysis was insensitive due to spontaneous adoption of interventions across conditions.

Trial Registration: ISRCTN10492618 (20 August 2015).
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http://dx.doi.org/10.1186/s12916-019-1324-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6521363PMC
May 2019

Diagnosis and management of chondral delamination injuries of the knee.

Knee 2019 Jun 26;26(3):647-652. Epub 2019 Apr 26.

Fortius Clinic, London, United Kingdom.

Background: Chondral delamination with intact articular surface is an under-recognised entity with no previous reports on how it should be managed. The purpose of this article is to increase awareness of this entity and make recommendations for its management.

Methods: We present a small case series of three patients who presented with knee pain and subsequent MRI scans revealed chondral delamination with intact articular surface as the only explanation of symptoms.

Results: Two of the lesions were located in the patella and one on the lateral aspect of the medial femoral condyle. All three were treated with bioabsorbable pin fixation. The delaminated area was easily recognised at arthroscopy by its bogginess on probing. All three patients made an excellent recovery and the lesions healed on MRI.

Conclusion: Chondral delamination with intact articular surface is best managed with bioabsorbable pin fixation so that it can be salvaged in order to optimise patient outcomes and avoid deterioration to a full thickness chondral lesion once the articular surface has separated.
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http://dx.doi.org/10.1016/j.knee.2019.04.007DOI Listing
June 2019

Magnetic resonance imaging appearances of the capsulo-osseous layer of the iliotibial band and femoral attachments of the iliotibial band in the normal and pivot-shift ACL injured knee.

Skeletal Radiol 2019 May 28;48(5):729-740. Epub 2018 Dec 28.

Department of Clinical Imaging, Imperial College Healthcare NHS Trust, Praed Street, London, W2 1NY, UK.

Background: Biomechanical evidence suggests that the anterolateral structures of the knee may be important restraints against anterolateral rotatory instability (ALRI) in the setting of anterior cruciate ligament (ACL) injury.

Objective: To describe the anatomy and presence of injury of the capsule-osseous layer of the iliotibial band (CITB), the iliotibial band, and its deep distal femoral attachments in patients with a 'normal' knee (no pivot-shift bone marrow edema (BME) pattern) and patients with a pivot-shift BME pattern indicative of a pivot-shift injury associated with ACL tears.

Methods: Group 1: 20 consecutive patients with no MRI evidence of pivot-shift injury and group 2: 20 consecutive patients with a pivot-shift BME pattern on MRI were identified. Retrospective consensus analysis of the anatomy and appearances of the CITB and the 'proximal' and 'epicondylar' distal femoral attachments of the ITB was performed for each MRI by two experienced musculoskeletal radiologists.

Results: The positive predictive value (PPV) of CITB injury for pivot-shift ACL injury was 74%, negative predicted Value (NPV) was 80%. The PPV for injury of the 'proximal' ITB femoral attachment with pivot-shift ACL injury was 93%, NPV was 84%. The PPV for 'epicondylar' iliotibial femoral attachment injury was 62%, NPV was 45%.

Conclusions: Injury of the CITB and 'proximal' deep femoral attachments of the ITB are good markers for ACL injury even in the absence of a Segond fracture and should be evaluated on all MRIs as they may prove important in the further management of ALRI.
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http://dx.doi.org/10.1007/s00256-018-3128-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6456473PMC
May 2019

A cadaveric model to evaluate the effect of unloading the medial quadriceps on patellar tracking and patellofemoral joint pressure and stability.

J Exp Orthop 2018 Sep 10;5(1):34. Epub 2018 Sep 10.

Biomechanics Group, Mechanical Engineering Department, Imperial College London, London, SW7 2AZ, UK.

Background: Vastus Medialis Muscles (VMM) damage has been widely identified following patellar dislocation. Rehabilitation programmes have been suggested to strengthen the VMM and reduce clinical symptoms of pain and instability. This controlled laboratory study investigated the hypothesis that reduced Vastus Medialis Obliquus (VMO) and Vastus Medialis Longus (VML) muscle tension would alter patellar tracking, stability and PFJ contact pressures.

Methods: Nine fresh-frozen dissected cadaveric knees were mounted in a rig with the quadriceps and iliotibial band loaded to 205 N. An optical tracking system measured joint kinematics and pressure sensitive film between the patella and trochlea measured PFJ contact pressures. Measurements were repeated for three conditions: 1. With all quadriceps heads and iliotibial band (ITB) loaded; 2. as 1, but with the VMO muscle unloaded and 3. as 1, but with the VMO and VML unloaded. Measurements were also repeated for the three conditions with a 10 N lateral displacement force applied to the patella.

Results: Reduction of VMM tension resulted in significant increases in lateral patellar tilt (2.8°) and translation (4 mm), with elevated lateral and reduced medial joint contact pressures from 0.48 to 0.14 MPa, and reduced patellar stability (all p < 0.05).

Conclusions: These findings provide basic scientific rationale to support the role of quadriceps strengthening to resist patellar lateral maltracking and rebalance the articular contact pressure away from the lateral facet in patients with normal patellofemoral joint anatomy.
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http://dx.doi.org/10.1186/s40634-018-0150-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6131679PMC
September 2018

Effect of Anterolateral Complex Sectioning and Tenodesis on Patellar Kinematics and Patellofemoral Joint Contact Pressures.

Am J Sports Med 2018 10 20;46(12):2922-2928. Epub 2018 Aug 20.

Biomechanics Group, Department of Mechanical Engineering, Faculty of Engineering, Imperial College London, London, UK.

Background: Anterolateral complex injuries are becoming more recognized. While these are known to affect tibiofemoral mechanics, it is not known how they affect patellofemoral joint behavior.

Purpose: To determine the effect of (1) sectioning the anterolateral complex and (2) performing a MacIntosh tenodesis under various conditions on patellofemoral contact mechanics and kinematics.

Study Design: Controlled laboratory study.

Methods: Eight fresh-frozen cadaveric knees were tested in a customized rig, with the femur fixed and tibia free to move, with optical tracking to record patellar kinematics and with thin pressure sensors to record patellofemoral contact pressures at 0°, 30°, 60°, and 90° of knee flexion. The quadriceps and iliotibial tract were loaded with 205 N throughout testing. Intact and anterolateral complex-sectioned states were tested, followed by 4 randomized tenodeses applying 20- and 80-N graft tension, each with the tibia in its neutral intact alignment or left free to rotate. Statistical analyses were undertaken with repeated measures analysis of variance, Bonferroni post hoc analysis, and paired samples t tests.

Results: Patellar kinematics and contact pressures were not significantly altered after sectioning of the anterolateral complex (all: P > .05). Similarly, they were not significantly different from the intact knee in tenodeses performed when fixed tibial rotation was combined with 20- or 80-N graft tension (all: P > .05). However, grafts tensioned with 20 N and 80 N while the tibia was free hanging resulted in significant increases in lateral patellar tilt ( P < .05), and significantly elevated lateral peak patellofemoral pressures ( P < .05) were observed for 80 N.

Conclusion: This work did not find that an anterolateral injury altered patellofemoral mechanics or kinematics, but adding a lateral tenodesis can elevate lateral contact pressures and induce lateral patellar tilting if the tibia is pulled into external rotation by the tenodesis. Although these in vitro changes were small and might not be relevant in a fully loaded knee, controlling the position of the tibia at graft fixation is effective in avoiding overconstraint at time zero in a lateral tenodesis.

Clinical Relevance: Small changes in lateral patellar tilt and patellofemoral contact pressures were found at time zero with a MacIntosh tenodesis. These changes were eliminated when the tibia was held in neutral rotation at the time of graft fixation. The risk of overconstraint after a lateral tenodesis therefore seems low and in accordance with recent published reports.
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http://dx.doi.org/10.1177/0363546518790248DOI Listing
October 2018

Author Reply to Letters to the Editor From Sonnery-Cottet et al. and Ferretti.

Authors:
Andy Williams

Arthroscopy 2018 08;34(8):2266-2268

Fortius Clinic, London, United Kingdom.

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http://dx.doi.org/10.1016/j.arthro.2018.05.015DOI Listing
August 2018

It is safe and effective to use all inside meniscal repair devices for posteromedial meniscal 'ramp' lesions.

Knee Surg Sports Traumatol Arthrosc 2018 Aug 12;26(8):2310-2316. Epub 2018 May 12.

Fortius Clinic, 17 Fitzhardinge Street, London, W1H 6EQ, UK.

Purpose: Recently, it has been recognized that meniscocapsular ('ramp') lesions of the posterior one-third of the medial meniscus frequently occur during injuries causing ACL rupture, and that these lesions are easily missed at arthroscopy. Furthermore, it is clear that these lesions are biomechanically significant, adding to the deficits caused by ACL rupture, and that their repair can reverse this. The efficacy of an all inside repair technique has been questioned by some authors and by those who advocate a suture shuttle technique via an accessory posteromedial portal. The use of Ultra FastFix and FastFix 360 meniscal repair devices to repair posteromedial meniscocapsular separations was investigated in terms of safe deployment and the effectiveness.

Methods: Twenty cadaveric fresh frozen knees were used-ten in each of two groups. A ramp lesion was created using a Beaver knife. The lesion was then repaired with either 4 Ultra FastFix (Smith and Nephew) or 4 FastFix 360 (Smith and Nephew) meniscal repair devices. The knees were put through a standardized loading cycle consisting of 10 Lachman's tests and ten maximum loading manual anterior drawer tests at 90° of flexion. Each knee was then flexed and extended fully ten times. The specimens were sectioned just proximal to the menisci and each suture anchor identified and its position recorded and photographed.

Results: In the Ultra FastFix group, a single anchor was found to be in an intra-articular position-a failure rate of 2.5%. In the FastFix 360 group, 5 anchors failed-a 12.5% failure rate. In all cases, the anchors were attached to their suture and so not truly loose within the joint.

Conclusions: This study confirms the safe and effective deployment of an all inside repair device for repair of medial meniscal 'ramp' lesions, and therefore its use is advocated in treating these difficult lesions. Ultra FastFix had the lower failure rate of 2.5%, which the authors believe is acceptable, and makes this device preferable to the FastFix360.
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http://dx.doi.org/10.1007/s00167-018-4976-5DOI Listing
August 2018

The infrapatellar fat pad is a dynamic and mobile structure, which deforms during knee motion, and has proximal extensions which wrap around the patella.

Knee Surg Sports Traumatol Arthrosc 2018 Nov 20;26(11):3515-3524. Epub 2018 Apr 20.

Fortius Clinic, 17 Fitzhardinge St, London, W1H 6EQ, UK.

Purpose: The infrapatellar fat pad (IFP) is a common cause of knee pain and loss of knee flexion and extension. However, its anatomy and behavior are not consistently defined.

Methods: Thirty-six unpaired fresh frozen knees (median age 34 years, range 21-68) were dissected, and IFP attachments and volume measured. The rectus femoris was elevated, suprapatellar pouch opened and videos recorded looking inferiorly along the femoral shaft at the IFP as the knee was flexed. The patellar retinacula were incised and the patella reflected distally. The attachment of the ligamentum mucosum (LMuc) to the intercondylar notch was released from the anterior cruciate ligament (ACL), both menisci and to the tibia via meniscotibial ligaments. IFP strands projecting along both sides of the patella were elevated and the IFP dissected from the inferior patellar pole. Magnetic resonance imaging (MRI) of one knee at ten flexion angles was performed and the IFP, patella, tibia and femur segmented.

Results: In all specimens the IFP attached to the inferior patellar pole, femoral intercondylar notch (via the LMuc), proximal patellar tendon, intermeniscal ligament, both menisci and the anterior tibia via the meniscotibial ligaments. In 30 specimens the IFP attached to the anterior ACL fibers via the LMuc, and in 29 specimens it attached directly to the central anterior tibia. Proximal IFP extensions were identified alongside the patella in all specimens and visible on MRI [medially (100% of specimens), mean length 56.2 ± 8.9 mm, laterally (83%), mean length 23.9 ± 6.2 mm]. Mean IFP volume was 29.2 ± 6.1 ml. The LMuc, attached near the base of the middle IFP lobe, acting as a 'tether' drawing it superiorly during knee extension. The medial lobe consistently had a pedicle superomedially, positioned between the patella and medial trochlea. MRI scans demonstrated how the space between the anterior tibia and patellar tendon ('the anterior interval') narrowed during knee flexion, displacing the IFP superiorly and posteriorly as it conformed to the trochlear and intercondylar notch surfaces.

Conclusion: Proximal IFP extensions are a novel description. The IFP is a dynamic structure, displacing significantly during knee motion, which is, therefore, vulnerable to interference from trauma or repetitive overload. Given that this trauma is often surgical, it may be appropriate that surgeons learn to minimize injury to the fat pad at surgery.
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http://dx.doi.org/10.1007/s00167-018-4943-1DOI Listing
November 2018

Editorial Commentary: The Anterolateral Ligament: The Emperor's New Clothes?

Authors:
Andy Williams

Arthroscopy 2018 04;34(4):1015-1021

London, United Kingdom.

In the following editorial commentary, the lateral soft tissues responsible for resisting the pivot shift phenomenon with the anterior cruciate ligament (ACL) are considered. The recent history of the anterolateral ligament (ALL) has led to rapid adoption of surgical techniques that have often not been investigated with scientific due process. A step-by-step approach starts with biomechanical testing to establish the anatomy and biomechanical characteristics of soft tissue structures and questions the importance of the ALL and proposes a more important role for the iliotibial band (ITB) passing between attachments to the distal lateral femur and tibia. Subsequent laboratory testing of various operative options shows superiority of lateral extra-articular tenodeses (LETs) as compared with ALL reconstruction.
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http://dx.doi.org/10.1016/j.arthro.2017.12.026DOI Listing
April 2018

Do We Need Extra-Articular Reconstructive Surgery?

Clin Sports Med 2018 Jan 19;37(1):61-73. Epub 2017 Sep 19.

Imperial College London, Exhibiton Road, London SW7 2AZ, UK; Fortius Clinic, 17 Fitzhardige Street, London W1H 6EQ, UK. Electronic address:

With renewed interest in the lateral soft tissue envelope anatomy, there is also a rise in the popularity of extra-articular anterolateral procedures. There is reasonable laboratory-based evidence for additional benefit of such procedures, but clinical data are not sufficient to judge outcome in the long term for better or worse. Furthermore, the decision-making process to decide when to add an extra-articular procedure is lacking; there are no clinical tests or investigations to guide the clinician. This article presents an overview of the literature and reflections from the authors on the subject.
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http://dx.doi.org/10.1016/j.csm.2017.07.008DOI Listing
January 2018

Biomechanics of the Anterolateral Structures of the Knee.

Clin Sports Med 2018 Jan 20;37(1):21-31. Epub 2017 Sep 20.

Biomechanics Group, Mechanical Engineering Department, Imperial College London, London SW7 2AZ, UK; Musculoskeletal Surgery Group, Imperial College School of Medicine, Charing Cross Hospital, London W6 8RF, UK. Electronic address:

This article describes the complex anatomic structures that pass across the lateral aspect of the knee, particularly the iliotibial tract and the underlying anterolateral ligament and capsule. It provides data on their strength and roles in controlling tibiofemoral joint laxity and stability. These findings are discussed in relation to surgery to repair or reconstruct the anatomic structures, or to create tenodeses with similar effect.
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http://dx.doi.org/10.1016/j.csm.2017.07.004DOI Listing
January 2018

Anterolateral Tenodesis or Anterolateral Ligament Complex Reconstruction: Effect of Flexion Angle at Graft Fixation When Combined With ACL Reconstruction.

Am J Sports Med 2017 Nov 12;45(13):3089-3097. Epub 2017 Sep 12.

Biomechanics Group, Mechanical Engineering Department, Imperial College London, London, UK.

Background: Despite numerous technical descriptions of anterolateral procedures, knowledge is limited regarding the effect of knee flexion angle during graft fixation.

Purpose: To determine the effect of knee flexion angle during graft fixation on tibiofemoral joint kinematics for a modified Lemaire tenodesis or an anterolateral ligament (ALL) complex reconstruction combined with anterior cruciate ligament (ACL) reconstruction.

Study Design: Controlled laboratory study.

Methods: Twelve cadaveric knees were mounted in a test rig with kinematics recorded from 0° to 90° flexion. Loads applied to the tibia were 90-N anterior translation, 5-N·m internal tibial rotation, and combined 90-N anterior force and 5-N·m internal rotation. Intact, ACL-deficient, and combined ACL plus anterolateral-deficient states were tested, and then ACL reconstruction was performed and testing was repeated. Thereafter, modified Lemaire tenodeses and ALL procedures with graft fixation at 0°, 30°, and 60° of knee flexion and 20-N graft tension were performed combined with the ACL reconstruction, and repeat testing was performed throughout. Repeated-measures analysis of variance and Bonferroni-adjusted t tests were used for statistical analysis.

Results: In combined ACL and anterolateral deficiency, isolated ACL reconstruction left residual laxity for both anterior translation and internal rotation. Anterior translation was restored for all combinations of ACL and anterolateral procedures. The combined ACL reconstruction and ALL procedure restored intact knee kinematics when the graft was fixed in full extension, but when the graft was fixed in 30° and 60°, the combined procedure left residual laxity in internal rotation ( P = .043). The combined ACL reconstruction and modified Lemaire procedure restored internal rotation regardless of knee flexion angle at graft fixation. When the combined ACL reconstruction and lateral procedure states were compared with the ACL-only reconstructed state, a significant reduction in internal rotation laxity was seen with the modified Lemaire tenodesis but not with the ALL procedure.

Conclusion: In a knee with combined ACL and anterolateral ligament injuries, the modified Lemaire tenodesis combined with ACL reconstruction restored normal laxities at all angles of flexion for graft fixation (0°, 30°, or 60°), with 20 N of tension. The combined ACL and ALL procedure restored intact knee kinematics when tensioned in full extension.

Clinical Relevance: In combined anterolateral procedure plus intra-articular ACL reconstruction, the knee flexion angle is important when fixing the graft. A modified Lemaire procedure restored intact knee laxities when fixation was performed at 0°, 30°, or 60° of flexion. The ALL procedure restored normal laxities only when fixation occurred in full extension.
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http://dx.doi.org/10.1177/0363546517724422DOI Listing
November 2017