Relevant bibliographies by topics / Unicompartmental Knee Replacement (UKR)

Academic literature on the topic 'Unicompartmental Knee Replacement (UKR)'

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Published: 10 March 2023

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Journal articles on the topic "Unicompartmental Knee Replacement (UKR)"

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Kennedy, J. A., E. Burn, H. R. Mohammad, S. J. Mellon, A. Judge, and D. W. Murray. "Lifetime revision risk for medial unicompartmental knee replacement is lower than expected." Knee Surgery, Sports Traumatology, Arthroscopy 28, no. 12 (February 12, 2020): 3935–41. http://dx.doi.org/10.1007/s00167-020-05863-3.

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Abstract Purpose Unicompartmental knee replacement (UKR) is widely considered to be a pre-total knee replacement (TKR) particularly in the young. The implication of this is that it is sensible to do a UKR, even though it will be revised at some stage, as it will delay the need for a TKR. The chance of a UKR being revised during a patient’s life time has not previously been calculated. The aim of this study was to estimate this lifetime revision risks for patients of different ages undergoing UKR. Methods Calculations were based on data from a designer series of 1000 medial Oxford UKR with mean 10-year follow up. These UKR were implanted for the recommended indications using the recommended surgical technique. Parametric survival models were developed for patients of different ages based on observed data, and were extrapolated using a Markov model to estimate lifetime revision risk. Results The estimated lifetime revision risk reduced with increasing age at surgery. Lifetime revision risk at age 55 was 15% (95% CI 12–19), at 65 it was 11% (8–13), at 75 it was 7% (5–9), and at 85 it was 4% (3–5). Conclusion Provided UKR is used appropriately, the lifetime revision risk is markedly lower than expected. UKR should be considered to be a definitive knee replacement rather than a Pre-TKR even in the young. These lifetime estimates, alongside established benefits for UKR in speed of recovery, morbidity, mortality and function, can be discussed with appropriate patients when considering whether to implant a UKR or TKR. Level of evidence III.
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Yu, Hiu-Kiu, Bruce Yan-Ho Tang, Hok-Leung Wong, Sumire Sasaki, and Tai-Fong Wong. "Better immediate and early postoperative outcomes of unicompartmental knee replacement comparing with total knee replacement: A matched cohort of patients with medial knee osteoarthritis." Journal of Orthopaedics, Trauma and Rehabilitation 28 (January 2021): 221049172110569. http://dx.doi.org/10.1177/22104917211056951.

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Introduction: This study compared the immediate and early postoperative outcomes of medial compartment knee osteoarthritis patients receiving unicompartmental knee replacement (UKR) with a matched cohort of total knee replacement (TKR). Methods: 26 UKR patients were matched with 26 TKR patients based on age, body mass index, pre-operative radiographic severity, range of motion (ROM), Knee Society score (KSS) and Feller patella score. Immediate postoperative outcomes were reflected by postoperative pain, blood loss, length of stay and the number of physiotherapy sessions attended. Early postoperative outcomes (ROM and KSS) were measured at 3 months and 1 year post-operatively. Results: UKR patients had less hemoglobin drop (UKR: 1.2 g/dL, TKR: 1.6 g/dL, p = 0.04), shorter length of stay (UKR: 4.3 days, TKR: 6.0 days, p < 0.001) and required less physiotherapy sessions for recovery (UKR: 6.9 sessions, TKR: 9.3 sessions, p < 0.05). There were no statistically significant differences in early post-operative pain score and postoperative analgesia use ( p > 0.05) between the two groups. Patients receiving UKR had significantly higher post-operative KSS (UKR: 155.9, TKR: 142.4, p = 0.005) and ROM (UKR: 115.8o, TKR: 98.8o, p < 0.001) at 3 months. The KSS and ROM of UKR group at 3 months was better than TKR group at 1-year follow-up. Conclusion: In patients with medial knee osteoarthritis, UKR showed less postoperative analgesic use and blood loss, shorter length of stay, shorter course of rehabilitation and faster recovery with better early KSS and ROM than TKR. Follow up is necessary for comparison in long term outcome and survivorship between the two groups.
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Ventura, Alberto, Claudio Legnani, Clara Terzaghi, Vittorio Macchi, and Enrico Borgo. "Unicompartmental Knee Replacement Combined to Anterior Cruciate Ligament Reconstruction: Midterm Results." Journal of Knee Surgery 33, no. 11 (July 3, 2019): 1152–56. http://dx.doi.org/10.1055/s-0039-1692647.

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AbstractA study was conducted to retrospectively evaluate the outcomes of combined medial unicompartmental knee replacement (UKR) and anterior cruciate ligament (ACL) reconstruction. The hypothesis was that this procedure would lead to satisfying results in patients affected by medial osteoarthritis and ACL insufficiency. Fourteen patients with ACL deficiency and concomitant medial compartment symptomatic osteoarthritis were treated from 2006 to 2010. Twelve of them were followed-up for an average time of 7.8 year (range: 6–10 years). Assessment included Knee Osteoarthritis Outcome score (KOOS), Oxford Knee score (OKS), American Knee Society scores (AKSS), Western Ontario and McMaster (WOMAC) index of osteoarthritis, Tegner's activity level, objective examination including instrumented laxity test with KT-1000 arthrometer, and standard X-rays. KOOS score, OKS, WOMAC index, and the AKSS improved significantly at follow-up (p < 0.001). There was no clinical evidence of instability in any of the knees as evaluated with clinical and instrumented laxity testing (p < 0.001). No pathologic radiolucent lines were observed around the components. In one patient, a total knee prosthesis was implanted due to the progression of signs of osteoarthritis in the lateral compartment 3 years after primary surgery. UKR combined with ACL reconstruction is an effective therapeutic option for the treatment of combined medial unicompartmental knee osteoarthritis and ACL deficiency and confirms subjective and objective clinical improvement up to 8 years after surgery. This study reflects level IV evidence.
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Hariri, Mustafa, Merlin Hagemann, Paul Mick, Julian Deisenhofer, Benjamin Panzram, Moritz Innmann, Tobias Reiner, Tobias Renkawitz, and Tilman Walker. "Physical Activity of Young Patients Following Minimally Invasive Lateral Unicompartmental Knee Replacement." Journal of Clinical Medicine 12, no. 2 (January 12, 2023): 635. http://dx.doi.org/10.3390/jcm12020635.

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Unicompartmental knee replacement (UKR) has increased in popularity in recent years, especially in young patients with high demands on their athletic ability. To date, there are no data available on the physical activity of young patients following lateral UKR. The aim of this study was to demonstrate return-to-activity rate and sporting activity of patients aged 60 years or younger following lateral UKR with a fixed-bearing (FB) prosthesis. Thirty-seven patients aged 60 years or younger after lateral FB-UKR were included. Sporting activities were assessed using the University of California Los Angeles activity scale (UCLA) and the Tegner activity score (TAS). Clinical outcome was measured using the Oxford Knee Score (OKS), range of motion (ROM) and visual analogue scale (VAS). The mean follow-up (FU) was 3.1 ± 1.5 years and the mean age at surgery was 52.8 ± 3.1 years. The return-to-activity rate was 87.5% and 49% of patients were highly active postoperatively as defined by an UCLA score of 7 or higher. All clinical parameters increased significantly postoperatively. We demonstrated a high return-to-activity rate with nearly half of the patients achieving high activity levels. Longer FU periods are necessary to evaluate the effect of activity on implant survival.
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Rajani, Amyn M., Kareena Rajani, Urvil A. Shah, Anmol RS Mittal, Rahul Sheth, and Meenakshi Punamiya. "Pseudoaneurysm of the Lateral Genicular Artery Following Unicompartmental knee Arthroplasty: A Rare Case Report." Journal of Orthopaedic Case Reports 12, no. 8 (2022): 57–60. http://dx.doi.org/10.13107/jocr.2022.v12.i08.2964.

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Introduction: Unicondylar knee replacement is a minimally invasive technique of surface replacement of the knee joint. Very little literature is available regarding vascular complications in patients who undergo this procedure due to their extremely rare nature. Case Report: This first-of-its-kind report describes a case of pseudoaneurysm of the lateral genicular artery of the right knee in a hypertensive, 65-year-old man, following a single sitting bilateral unicompartmental knee replacement (UKR). With no involvement of the lateral compartment in UKR, we suspect an underlying mechanical element as the cause of the pseudoaneurysm. Patient presented with swelling and pain in the right knee for the first time at 8-month postoperatively, and after aspiration of the hemarthrosis, had two events of recurrence with increasing frequency. Dynamic magnetic resonance angiography confirmed the diagnosis and the patient underwent angiography-guided embolization of the lateral genicular artery using polyvinyl alcohol particles, with no recurrence in over a year since then. Conclusion: Pseudoaneurysm of the lateral genicular artery is a possible cause of recurrent hemarthrosis even after unicondylar knee replacement and requires a high degree of suspicion for its timely diagnosis and management.
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Panzram, Benjamin, Mira Mandery, Tobias Reiner, Tobias Gotterbarm, Marcus Schiltenwolf, and Christian Merle. "Cementless Oxford Medial Unicompartmental Knee Replacement—Clinical and Radiological Results of 228 Knees with a Minimum 2-Year Follow-Up." Journal of Clinical Medicine 9, no. 5 (May 14, 2020): 1476. http://dx.doi.org/10.3390/jcm9051476.

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(1) Background: Studies show several advantages of unicompartmental knee replacement (UKR) over total knee replacements (TKR), whereas registry based revision rates of UKR are significantly higher than for TKA. Registry data report lower revision rates for cementless UKR compared to cemented UKR. The aim of this study was to assess clinical and radiological results of cementless Oxford UKR (OUKR) in an independent cohort. (2) Methods: This retrospective cohort study examines a consecutive series of 228 cementless OUKR. Clinical outcome was measured using functional scores (Oxford Knee Score (OKS), American Knee Society Score (AKSS), Hannover Functional Ability Questionnaire for Osteoarthritis (FFbH-OA), range of motion (ROM)), pain and satisfaction. Radiographs were analyzed regarding the incidence of radiolucent lines (RL), implant positioning, and their possible impact on clinical outcome. (3) Results: At a mean follow-up of 37.1 months, the two and three year revision free survival-rates were 97.5% and 96.9%. Reasons for revision surgery were progression of osteoarthritis, inlay dislocation and pain. All clinical outcome scores showed a significant improvement from pre- to postoperative. The incidence of RL around the implant was highest within the first year postoperatively (36%), and decreased (5%) within the second year. Their presence was not correlated with inferior clinical outcome. Implant positioning showed no influence on clinical outcome. (4) Conclusion: Cementless OUKR showed excellent clinical outcome and survival rates, with reliable osteointegration. Neither the incidence of radiolucent lines nor implant positioning were associated with inferior clinical outcome.
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Daly, D., and R. Maxwell. "TEN YEARS OF COMBINED ACL RECONSTRUCTION AND UNICOMPARTMENTAL KNEE ARTHROPLASTIES." Orthopaedic Proceedings 105-B, SUPP_2 (February 2023): 60. http://dx.doi.org/10.1302/1358-992x.2023.2.060.

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The purpose of this study is to assess the long term results of combined ACL reconstruction and unicompartmental knee replacements (UKR). These patients have been selected for this combined operation due to their combination of instability symptoms from an absent ACL and unicompartmental arthritis.Retrospective review of 44 combined UKR and ACL reconstruction by a single surgeon. Surgeries included both medial and lateral UKR combined with either revision ACL reconstruction or primary ACL reconstruction. Patient reported outcomes were obtained preoperatively, at one year, 5 years and 10 years. Revision rate was followed up over 13 years for a mean of 7.4 years post-surgery.The average Oxford score at one year was 43 with an average increase from pre-operation to 1 year post operation of 15. For the 7 patients with 10 year follow up average oxford score was 42 at 1 year, 43 at 5 years and 45 at 10 years.There were 5 reoperations. 2 for revision to total knee arthroplasty and 1 for an exchange of bearing due to wear. The other 2 were the addition of another UKR. For those requiring reoperation the average time was 8 years.Younger more active patients presenting with ACL deficiency causing instability and unicompartmental arthritis are a difficult group to manage. Combining UKR and ACL reconstruction has scant evidence in regard to long term follow up but is a viable option for this select group. This paper has one of the largest cohorts with a reasonable follow up averaging 7.4 years and a revision rate of 11 percent.Combined unilateral knee replacements and ACL reconstruction can be a successful operation for patients with ACL rupture causing instability and unicompartmental arthritis.
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Tang, Bruce Yan Ho, Chi Nok Cheung, Hon For Tsui, and Hok Leung Wong. "Early promising result of bicompartmental knee replacement in middle-aged patients." Journal of Orthopaedics, Trauma and Rehabilitation 26, no. 2 (June 13, 2019): 85–88. http://dx.doi.org/10.1177/2210491719848758.

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Introduction: Partial knee replacement (PKR) is one of the treatment options in middle-aged patients with less extensive knee osteoarthritis, with unicompartmental knee replacement (UKR) most commonly done for medial osteoarthritis. There are numerous advantages like bone/ligament preserving and faster recovery. However, the indications of UKR remain controversial, as most patients have some patellofemoral joint (PFJ) osteoarthritis. We performed modular bicruciate-retaining bicompartmental knee replacement (BKR) in this group of patients and compared the outcome with total knee replacement (TKR). Materials and Methods: From 2016 to 2017, 14 BKR were performed in patients with medial and PFJ osteoarthritis. They were retrospectively compared with 14 TKR performed in patients with similar age and severity. The incision length, operative time, blood loss (in terms of hemoglobin drop), and length of stay were recorded. Pre- and postoperative range of motion and Knee Society knee score at 1-year follow-up were compared. Results: The mean incision length for BKR was shorter than TKR (130.1 vs. 185.1 mm), but the mean operative time was also longer (152.6 vs. 88.1 min). There was also less mean hemoglobin drop (1.8 vs. 2.6 g/dL) and shorter length of stay (7.4 vs. 9.2 days). The mean postoperative function score is better in BKR group (90.4 vs. 77.5), and the mean postoperative knee score (87.2 vs 88.9) and flexion (115.7° vs. 111.4°) were similar for both groups. Discussion: In selected patients, BKR is a good alternative to TKR. It preserves advantages of UKR while also tackle the PFJ which is the most controversial aspect of UKR. The early clinical outcome in our study is promising. However, there is a learning curve. Longer follow-up is necessary to study on the performance and survivorship as compared with UKR and TKR.
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Spinelli, M., S. Affatato, M. K. Harman, and J. D. DesJardins. "Bi-unicondylar knee prosthesis functional assessment utilizing force-control wear testing." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 224, no. 7 (December 28, 2009): 813–21. http://dx.doi.org/10.1243/09544119jeim726.

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Recent in vivo studies have identified variations in knee prosthesis function depending on prosthesis geometry, kinematic conditions, and the absence/presence of soft-tissue constraints after knee replacement surgery. In particular, unicondylar knee replacements (UKR) are highly sensitive to such variations. However, rigorous descriptions of UKR function through experimental simulation studies, performed under physiological force-controlled conditions, are lacking. The current study evaluated the long-term functional performance of a widely used fixed-bearing unicompartmental knee replacement, mounted in a bi-unicondylar configuration (Bi-UKR), utilizing a force-controlled knee simulator during a simulated (ISO 14243) walking cycle. The wear behaviour, the femoral—tibial kinematics, and the incurred damage scars were analysed. The wear rates for the medial and the lateral compartments were 10.27 ± 1.83 mg/million cycles and 4.49 ± 0.53 mg/million cycles, respectively. Although constant-input force-controlled loading conditions were maintained throughout the simulation, femoral—tibial contact point kinematics decreased by 65 to 68 per cent for average anterior/posterior travel and by 58 to 74 per cent for average medial/lateral travel with increasing cycling time up to 2 million cycles. There were no significant differences in damage area or damage extent between the medial and the lateral compartments. Focal damage scars representing the working region of the femoral component on the articular surface extended over a range of 16—21 mm in the anterior—posterior direction. Kinematics on the shear plane showed slight variations with increasing cycling time, and the platform exhibited medial pivoting over the entire test. These measures provide valuable experimental insight into the effect of the prosthesis design on wear, kinematics, and working area. These functional assessments of Bi-UKR under force-controlled knee joint wear simulation show that accumulated changes in the UKR articular conformity manifested as altered kinematics both for anterior/posterior translations and internal/external rotations.
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Mowbray, J., C. Frampton, R. Maxwell, and G. Hooper. "SIXTEEN-YEAR SURVIVAL AND FUNCTIONAL RESULTS OF THE CEMENTLESS OXFORD UNICOMPARTMENTAL KNEE REPLACEMENT." Orthopaedic Proceedings 105-B, SUPP_2 (February 2023): 95. http://dx.doi.org/10.1302/1358-992x.2023.2.095.

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Cementless fixation is an alternative to cemented unicompartmental knee replacement (UKR), with several advantages over cementation. This study reports on the 15-year survival and 10-year clinical outcomes of the cementless Oxford unicompartmental knee replacement (OUKR).This prospective study describes the clinical outcomes and survival of first 693 consecutive cementless medial OUKRs implanted in New Zealand.The sixteen-year survival was 89.2%, with forty-six knees being revised. The commonest reason for revision was progression of arthritis, which occurred in twenty-three knees, followed by primary dislocation of the bearing, which occurred in nine knees. There were two bearing dislocations secondary to trauma and a ruptured ACL, and two tibial plateau fractures. There were four revisions for polyethylene wear. There were four revisions for aseptic tibial loosening, and one revision for impingement secondary to overhang of the tibial component. There was only one revision for deep infection and one revision where the indication was not stated. The mean OKS improved from 23.3 (7.4 SD) to 40.59 (SD 6.8) at a mean follow-up of sixteen years.In conclusion, the cementless OUKR is a safe and reproducible procedure with excellent sixteen-year survival and clinical outcomes.
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Dissertations / Theses on the topic "Unicompartmental Knee Replacement (UKR)"

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Van, den Heever David Jacobus. "Development of patient-specific knee joint prostheses for unicompartmental knee replacement (UKR)." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17942.

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Thesis (PhD)--Stellenbosch University, 2011.
ENGLISH ABSTRACT: The knee is the largest, most complicated and incongruent joint in the human body. It sustains very high forces and is susceptible to injury and disease. Osteoarthritis is a common disease prevalent among the elderly and causes softening or degradation of the cartilage and subcondral bone in the joint, which leads to a loss of function and pain. This problem can be alleviated through a surgical intervention commonly termed a “knee replacement”. The aim of a knee replacement procedure is to relieve pain and restore normal function. Ideally, the knee replacement prosthesis should have an articulating geometry similar to that of the patient’s healthy knee, and must allow for normal motion. Unfortunately, this is often problematic since knee prostheses are supplied in standard sizes from a variety of manufacturers and each one has a slightly different design. Furthermore, commercial prostheses are not always able to restore the complex geometry of an individual patient’s original articulating surfaces. This dissertation shows that there is a significant variation between knee geometries, regardless of gender and race. This research aims to resolve the problem in two parts: Firstly by presenting a method for preoperatively selecting the optimal knee prosthesis type and size for a specific patient, and secondly by presenting a design procedure for designing and manufacturing patient-specific unicompartmental knee replacements. The design procedure uses mathematical modelling and an artificial neural network to estimate the original and healthy articulating surfaces of a patient’s knee. The models are combined with medical images from the patient to create a knee prosthesis that is patient-specific. These patient-specific implants are then compared to conventional implants with respect to contact stresses and kinematics. The dissertation concludes that patient-specific implants can have characteristics that are comparable to or better than conventional prostheses. The unique design methodology presented in this dissertation introduces a significant advancement in knee replacement technology, with the potential to dramatically improve clinical outcomes of knee replacement surgery.
AFRIKAANSE OPSOMMING: Die knie is die grootste, mees komplekse en mees ongelyksoortige gewrig in die liggaam. Osteoarthritis is ’n siekte wat algemeen by bejaardes voorkom en die versagting of agteruitgang van die kraakbeen en subchondrale bene in die gewrig tot gevolg het, wat tot ’n verlies van funksionering en pyn lei. Hierdie probleem kan verlig word deur ’n chirurgiese ingryping wat algemeen as ’n “knievervanging” bekend staan. Die doel van ’n knievervangingsprosedure is om pyn te verlig en normale funksionering te herstel. Ideaal gesproke behoort die knievervangingsprostese ’n gewrigsgeometrie te hê wat soortgelyk aan die pasiënt se gesonde knie is, en normale beweging moontlik maak. Ongelukkig is dit dikwels problematies aangesien knieprosteses in standaardgroottes en deur ’n verskeidenheid vervaardigers verskaf word, wat elkeen se ontwerp effens anders maak. Verder kan kommersiële prosteses nie altyd die komplekse geometrie van ’n individuele pasiënt se oorspronklike gewrigsoppervlakke vervang nie. Hierdie proefskrif wys dat daar ’n betekenisvolle variasie tussen knieafmetings is, afgesien van geslag en ras. Hierdie navorsing is daarop gemik om die problem op tweërlei wyse te benader: Eerstens deur ’n metode aan te bied om die optimal knieprostesetipe en -grootte vir ’n spesifieke pasiënt voor die operasie uit te soek, en tweedens om ’n ontwerpprosedure aan te bied vir die ontwerp en vervaardiging van pasiëntspesifieke unikompartementele knievervangings. Die ontwerpprosedure gebruik wiskundige modellering en ’n kunsmatige neurale netwerk om die oorspronklike en gesonde gewrigsoppervlakke van ’n pasiënt se knie te bepaal. Die modelle word met mediese beelde van die pasiënt gekombineer om ’n knieprostese te skep wat pasiëntspesifiek is. Hierdie pasiëntspesifieke inplantings word dan met konvensionele inplantings vergelyk wat kontakstres en kinematika betref. Daar word tot die slotsom gekom dat die pasiëntspesifieke inplantings oor eienskappe kan beskik wat vergelykbaar is met of selfs beter is as dié van konvensionele prosteses. Die unieke ontwerpmetodologie wat in hierdie proefskrif aangebied word, stel beduidende vordering in knievervangingstegnologie bekend, met die potensiaal om die kliniese uitkomste van knievervangingsoperasies dramaties te verbeter.
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Liddle, Alexander David. "Failure of unicompartmental knee replacement." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:c5bd883f-7c6f-42fe-9231-68609acaf234.

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Unicompartmental knee replacement (UKR) is the principal alternative to total knee replacement (TKR) in the treatment of end-stage knee osteoarthritis. It involves less tissue resection, resulting in lower rates of morbidity and faster recoveries compared to TKR. However, UKR has a significantly higher revision rate compared to TKR. As a result, whilst over a third of patients are eligible for UKR, only around 8% receive it. A comprehensive comparison of matched patients undergoing TKR and UKR was undertaken using a large dataset from the National Joint Registry for England and Wales (NJR). Failure rates (revision, reoperation, complications and mortality), length of stay and patient-reported outcomes (PROMs) were studied. Whilst patients undergoing TKR had lower reoperation and revision rates, they had higher rates of morbidity and mortality, longer hospital stays, and inferior PROMs compared to UKR. The main reason for revision in UKR was loosening. In view of the high revision rate in UKR, NJR data was studied to identify modifiable risk factors for failure in UKR. Important patient factors were identified including age, gender and pre-operative function. Surgeons with a higher UKR caseload had significantly lower revision rates and superior patient-reported outcomes. Increasing usage (offering UKR to a greater proportion of knee replacement patients) appears to be a viable method of increasing caseload and therefore of improving results. Surgeons with optimal usage (around 50% of patients, using appropriate implants) achieved revision/reoperation rates similar to matched patients undergoing TKR. Two clinical studies were conducted to establish whether the use of cementless fixation would improve fixation and reduce the revision rate of UKR. Cementless UKR was demonstrated to be safe and reliable, with PROMs similar or superior to those demonstrated in cemented UKR. Patients with suboptimal cementless fixation were examined and pre-disposing technical factors were identified. Finally, using NJR data, the effect of the introduction of cementless UKR on overall outcomes was examined. The number of cementless cases was small, and no significant effect on implant survival was demonstrated. However, patients undergoing cementless UKR demonstrated superior PROMs. These studies demonstrate that UKR has numerous advantages over TKR in terms of morbidity, mortality and PROMs. If surgeons perform high volumes of UKR (achievable by increasing their UKR usage), these advantages can be attained without the large difference in revision rates previously demonstrated. Cementless UKR is safe and provides superior fixation and outcomes in the hands of high-volume surgeons. Further work is needed to quantify the revision rate of cementless UKR, and to assess its results in the hands of less experienced surgeons.
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Gulati, Aashish. "Outcome after medial unicompartmental knee replacement." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:94f8e366-dc86-4a0c-8ca6-be92e98ed3fb.

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Medial Oxford unicompartmental knee replacement (UKR) is an established and successful treatment for patients with antero-medial knee osteoarthritis. However, following the operation some patients have pain which compromises their functional outcome. The aims of this thesis were to determine the incidence of pain, to identify the patient, disease and surgical risk factors associated with this pain and to try and understand why it occurs. The clinical studies were performed using patients operated on by experienced surgeons. The incidence of post-operative severe pain was 3% at six weeks and 2% at one year and the incidence remained unchanged at subsequent follow ups. The overall incidence of pain has reduced over the years. In patients who had UKR between 1998 and 2001, the incidence of severe pain was 5%; this reduced to 2.3% for the period between 2008 and 2011. As the indications have not changed, the improvement is probably due to modifications in the surgical technique and due to improvements in instrumentation. Patients with severe pain at the final follow up had a worse neuropathic pain score, and the patients with possible pre-operative neuropathic pain achieved significantly worse outcome. To explore the effect of disease severity on outcome, matched cohorts of patients with partial thickness cartilage loss (PTCL), bone-on-bone and bone loss were compared. All those with bone-on-bone and bone loss did well, whereas 20% of those with PTCL did not benefit from the surgery; 7% had severe pain and 17% had pain related complications. Although component and leg alignment, and component overhang have a profound effect on the outcome of total knee replacement (TKR), their effect on the outcome of the Oxford UKR are not known. It was found that malalignment in the coronal or sagittal planes of the femoral component within ±10° and of the tibial component within ±5° did not compromise the outcome. Leg alignment was not related to outcome even though 18% were in 5° varus and 8% were in 10° varus. In contrast, tibial component overhang ≥3 mm compromised the outcome and 21% of these patients continue to suffer from pain. The presence of radiolucent lines (RLL) following a joint replacement is usually deemed to be indicative, or predictive, of loosening. 63% of Oxford UKRs were found to have RLL under the tibial component. No correlation was found between RLL and outcome, particularly pain. It has been suggested that post-operative pain, which is commonly antero-medial over the proximal tibia, may be related to bone overload. This was explored using the finite element (FE) analysis. Following implantation of the Oxford UKR, the strains in the antero-medial region doubled. Various implantation, loading and alignment variables were studied and the findings correlated with the clinical studies, suggesting that high strain is an important cause of pain. With time, the bone will remodel, so the strains will decrease but individual differences in the remodeling threshold may explain resolution of symptoms in some, but not in all, patients. In conclusion, this work has shown that following the Oxford UKR, pain is a rare but important complication. The chance of pain can be decreased by operating only on patients with bone-on-bone arthritis and taking care with the surgical technique. Bone overload is likely to be an important cause of pain, and further modification to the implant or technique, such as achieving fixation of the tibial component vertical wall to bone, may further decrease the incidence of pain.
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Kendrick, Benjamin J. L. "Fixation of the Oxford unicompartmental knee replacement." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:0137ea96-ca9a-4f4e-8a37-53602903f28f.

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The Oxford Unicompartmental Knee Replacement (UKR) is a commonly performed procedure, with a good clinical outcome at 15 years, however, radiolucent lines are commonly found beneath the tibial tray. With the projected increase in knee arthroplasty, particularly in younger patients, implant longevity is of paramount importance. The aim of this thesis is to understand how fixation is achieved with the Oxford UKR and how it can be improved. A histological study demonstrated that in the presence of a radiolucent line the tibial bone-cement interface is made up of a combination of direct bony contact, fibrocartilage and fibrous tissue. The radiolucency is more marked when there is more soft tissue. However in all cases there is some direct bony contact. Cemented and cementless fixation was compared in a randomised controlled study using radiostereometric analysis and fluoroscopic imaging of the interfaces. In the first year the cementless tibial component subsided on average 0.28 mm and had an increased posterior slope of 0.40°, whereas the cemented component only subsided 0.09 mm, with a 0.10° increase in slope. In the second year both components had very little further subsidence (mean<0.05 mm) and no increase in posterior slope. In the second year a single cementless tibial component subsided greater than 0.15 mm, whereas four cemented components, all with radiolucencies, subsided more than 0.15 mm. At two years the cemented components had a significantly higher prevalence of radiolucency (62% v 29%), with 24% having a complete radiolucency, whereas no cementless components had a complete radiolucency. Two designs of lateral UKR were also compared. These had a flat tibial component that predominantly transmits compressive loading, and a domed component that also transmits shear. There was a lower prevalence of radiolucency in the domed tibia (13% v 60%), even though there was a similar amount of migration as the cemented medial tibial component. In conclusion radiolucent lines, both partial and complete, are common with cemented components, and may, in part, be a result of compressive loading. They are associated with good long-term results and direct bone cement contact indicating satisfactory fixation. However, they are also associated with increased migration and soft tissue at the interface suggesting that the fixation, although satisfactory, is suboptimal. The cementless components had no complete radiolucencies and low levels of migration in the second year. This suggests that bone ingrowth and secure fixation occurs reliably, and therefore that cementless fixation may be better than cemented for the Oxford UKR.
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Newman, Simon David Standen. "Improving outcomes in knee arthroplasty : the lateral unicompartmental knee replacement." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/39290.

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Total knee replacement (TKR) continues to increase in popularity, but satisfying patients who remain active for longer is a major challenge. Outcomes from TKR remain suboptimal, with as many as 20% gaining little benefit. An alternative approach to TKR is the use of partial or unicompartmental knee replacements (UKR). These are smaller and safer operations, but are arguably more difficult to perform and have been associated with a higher rate of revision surgery. Whilst a great deal is understood about medial UKR, relatively little is known about lateral UKR and this procedure forms the basis of this thesis. Outcomes of a lateral UKR implant, the Oxford Domed Lateral Partial Knee were assessed through upto 10 year follow-up of the largest independent series of this implant and demonstrated similar rates of revision and Oxford Knee Scores to previously published medial UKR series. Further assessment of the gait of patients with the same implant however failed to show a significant improvement over demographically matched patients with TKR. Accuracy of implant positioning is important for achieving optimal outcomes. One technology that may assist in delivering expert level skill is patient specific instrumentation (PSI). For the first time, the effect of changes in PSI guide design were explored, demonstrating the importance of achieving multiplanar bone contact. The use of PSI guides compared to traditional instruments was associated with superior femoral implant positioning and a trend for superior tibial implant positioning when used by inexperienced surgeons on a training course. The effect of tibial implant malpositioning on tibial strain was demonstrated using digital image correlation. Excessive posterior slope and tibial resection should be avoided to prevent higher tibial strains that may result in fracture. A pre-requisite for successful arthroplasty, including lateral UKR, is the establishment of osseomechanical integration. Enhanced osseomechanical integration may be better achieved with strontium-substituted bioactive glass (SrBG) than a hydroxyapatite (HA) coating as demonstrated in a lapine model. The data presented in this thesis demonstrates that lateral UKR is a challenging but effective operation, though further development is required to facilitate normal gait. Further improvements in function and outcomes may be achievable through the use of PSI and enhanced implant fixation with SrBG coatings.
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Lewold, Stefan. "The Swedish knee arthroplasty study with special reference to unicompartmental prostheses /." Lund : Lund University Hospital, 1997. http://catalog.hathitrust.org/api/volumes/oclc/68945018.html.

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Mentink, Michael Johannes Antonius. "Measurement of bearing load in unicompartmental knee arthroplasty using an instrumented knee bearing." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:65a90ea6-77b6-49f2-9d8f-ecc4780dff81.

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The aim of this thesis was to investigate how to construct a system to measure load in a mobile unicompartmental knee replacement (UKR) bearing. In vivo loads have been measured in a total knee replacement (TKR), but with TKR the kinematics are different from those of the normal knee, whereas they are close to normal in a mobile UKR, so the loads measured by an instrumented UKR would be more representative of the normal knee. On the principle of measuring compression of an object under load, the load may be estimated. Compression measurement using a capacitive sensor was the optimal solution to measure load, based on life expectancy of the sensor and bearing integrity. A capacitive sensor within a polyethylene (UHMWPE) bearing has not been used before. The visco-elastic and temperature dependent properties of UHMWPE were determined with experiments. UHMWPE had an approximately linear response after ten minutes of applying a constant load. A temperature sensor should be used in vivo to compensate for temperature effects acting on the elastic modulus of UHMWPE. Finite element modelling demonstrated that positioning the sensor under the centre of the bearing concavity resulted in the largest capacitive change. The influence of various dimensional parameters on sensor output was simulated, and the conclusion was that the sensor only needs to be calibrated once. An electronic module inserted into a bearing had less than 5 % influence on bearing compression. Capacitive sensors were made from polyimide, using standard production methods, and embedded within a UKR bearing using the standard compression moulding process. The embedded sensor had a second order low pass frequency response, with a corner frequency of 9 Hz, twice the frequency required for typical functional loading such as gait. Physiological load signals, gait and step up/down, were applied to the bearing. The capacitance to load response was approximately linear. Load was estimated using a linear method and a dynamic method. The linear method performed best, with an accuracy of force estimation better than 90 %. In vitro tests were performed using a commercially available transceiver, two stan- dard antennas and a custom antenna, designed to be incorporated in the bearing. Wireless communication between an implanted custom antenna and an external an- tenna was shown to be feasible. Experiments were also performed that demonstrate that inductive powering of the bearing was feasible. In addition to load measurement, a proposal for dynamic measurement of the orien- tation angles of both the tibia and the femur was made. Power and volume calculations showed that it is possible to place an electronic module within the bearing. This thesis has not only demonstrated that it is feasible to make an instrumented bearing for UKR but has also provided a basic design for manufacturing.
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Scott, Chloe Elizabeth Henderson. "Effect of unicompartmental knee replacement tibial component design on proximal tibial strain and ongoing pain." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/23397.

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Introduction: Unicompartmental knee replacements (UKRs) are an alternative to total knee replacements (TKRs) for treating isolated medial compartment knee osteoarthritis. However, revision rates are consistently higher than for TKR and UKRs are commonly revised for “unexplained” pain, a possible cause of which is elevated proximal tibial bone strain. The influence of implant design on this strain has not been previously investigated. Aims: The aims of this thesis are to determine the effect of medial UKR tibial component design on proximal tibial strain and ongoing pain. Methods: A retrospective clinical cohort study was performed comparing patient reported outcome and implant survival of a metal backed mobile bearing UKR implant (n=289) and an all-polyethylene (AP) fixed bearing UKR implant (n=111) with minimum 5 year follow up. A method of digital radiological densitometry, the greyscale ratio b (GSRb), was developed, validated and applied to plain radiographs to measure changes in bone density over 5 years in both the metal backed (n=173) and all-polyethylene (n=72) UKR patients. A finite element model (FEM) was validated against previous mechanical testing data and was used to analyse the effect of metal backing and implant thickness on proximal tibial cancellous bone strain in fixed bearing UKR implants. Results: There were no significant differences in patient reported outcomes between implants throughout follow up. Ten year all cause survival was 90.2 (95%CI 86-94) for the metal backed implant and 79.9 (60.7 to 99) for the all-polyethylene. Revision for unexplained pain was significantly greater in the AP implant where revisions were performed significantly earlier. Overall, the mean GSRb reduced following medial UKR with no difference between implants. In those patients where GSRb increased, patient reported outcomes were worse with an association with ongoing pain. A finite element model was successfully validated using acoustic emission and digital image correlation data. This model confirmed that the volume of cancellous bone exposed to compressive and tensile strains in excess of 3000 (pathological overloading) and 7000 (fracture) microstrain were higher in the AP implants, as were peak tensile and compressive strains. Varying polyethylene insert thickness did not affect these strain parameters in the metal backed implant, but varying polyethylene thickness in the AP implants had significant effects at all loads with elevated strains in thinner implants. Increasing the AP thickness to 10mm did not reduce strains to the levels found under metal backed implants, and imminent cancellous bone failure was implied when AP thickness was reduced to 6mm. Conclusion: UKRs with all-polyethylene tibial components are associated with greater proximal tibial strains than metal backed implants and this is exacerbated in thinner implants. The clinical consequences of this are uncertain. Medial UKR implantation does alter proximal tibial GSRb, though this is not uniform and is independent of implant type. When GSRb increases it is associated with ongoing pain.
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SPINELLI, MICHELE. "Experimental tribological investigations of articular bearings for lower limb prosthesis." Doctoral thesis, 2009. http://hdl.handle.net/2158/590125.

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Books on the topic "Unicompartmental Knee Replacement (UKR)"

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P, Andriacchi Th, and Cartier Ph, eds. Unicompartmental knee arthroplasty. Paris: Expansion scientifique française, 1997.

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John, Goodfellow, ed. Unicompartmental arthroplasty with the Oxford knee. Oxford: Oxford University Press, 2006.

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Pandit, Hemant, Christopher Dodd, and David Murray. Unicompartmental knee replacement. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199550647.003.008013.

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♦ Ideal treatment option for end-stage osteoarthritis affecting a single compartment of the knee♦ Unicompartmental knee replacement has many advantages over total knee replacement• Restores near normal kinematics• Usually gives a better range of movement• Patients require a shorter hospital stay• Fewer serious complications
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4

Cartier, P., Jean-Alain M. D. Epinette, G. Deschamps, and P. Hernigou. Unicompartmental Knee Arthroplasty. Elsevier Science Ltd, 1997.

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John, O'Connor, John Goodfellow, David Murray, and Christopher Dodd. Unicompartmental Arthroplasty with the Oxford Knee. Goodfellow Publishers, Limited, 2011.

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John, O'Connor, John Goodfellow, David Murray, Christopher Dodd, and Hemant Pandit. Unicompartmental Arthroplasty with the Oxford Knee. Goodfellow Publishers, Limited, 2015.

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John, O'Connor, John Goodfellow, David Murray, and Christopher Dodd. Unicompartmental Arthroplasty with the Oxford Knee. Goodfellow Publishers, Limited, 2011.

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Unicompartmental Arthroplasty with the Oxford Knee. Goodfellow Publishers, Limited, 2015.

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O'Connor, John, John Goodfellow, David Murray, and Christopher Dodd. Unicompartmental Arthroplasty with the Oxford Knee (Oxford Medical Publications). Oxford University Press, USA, 2006.

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Book chapters on the topic "Unicompartmental Knee Replacement (UKR)"

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Böhler, Nikolaus. "Unicompartmental Knee Replacement (UKR)." In European Surgical Orthopaedics and Traumatology, 3155–62. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-34746-7_141.

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Newman, J. H. "Lateral Unicompartmental Knee Replacement." In The Knee Joint, 689–94. Paris: Springer Paris, 2012. http://dx.doi.org/10.1007/978-2-287-99353-4_62.

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Cobb, Justin, and Charles Rivière. "Unicompartmental Knee Arthroplasty." In Personalized Hip and Knee Joint Replacement, 207–18. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-24243-5_18.

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Murray, D. W., and J. W. Goodfellow. "Medial unicompartmental knee replacement." In Neues in der Knieendoprothetik, 19–23. Heidelberg: Steinkopff, 2003. http://dx.doi.org/10.1007/978-3-642-57368-2_5.

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Saghieh, Said. "Medial Unicompartmental Knee Replacement." In Operative Dictations in Orthopedic Surgery, 137–39. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-7479-1_37.

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Belzile, Etienne L., Michèle Angers, and Martin Bédard. "Custom Unicompartmental Knee Arthroplasty." In Personalized Hip and Knee Joint Replacement, 221–31. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-24243-5_19.

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Thermann, H. "Minimally Invasive Unicompartmental Knee Replacement." In New Techniques in Knee Surgery, 149–63. Heidelberg: Steinkopff, 2003. http://dx.doi.org/10.1007/978-3-642-57380-4_19.

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Elliott, Johanna, and Myles Coolican. "Biomechanics of Unicompartmental Knee Replacement." In Orthopaedic Biomechanics in Sports Medicine, 391–98. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-81549-3_30.

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Cobb, J. "Hands-on Robotic Unicompartmental Knee Replacement." In Navigation and MIS in Orthopedic Surgery, 284–96. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-36691-1_37.

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Barrett, William P. "Total Knee Arthroplasty Following Prior Unicompartmental Replacement." In Revision Total Knee Arthroplasty, 301–13. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-67344-8_21.

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Conference papers on the topic "Unicompartmental Knee Replacement (UKR)"

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Van Den Heever, D. J., C. Scheffer, P. J. Erasmus, and E. M. Dillon. "Contact stresses in a patient-specific unicompartmental knee replacement." In 2010 32nd Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2010). IEEE, 2010. http://dx.doi.org/10.1109/iembs.2010.5626194.

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Imran, Ahmed. "Knee laxity after unicompartmental joint replacement: A planar mathematical analysis." In 2011 1st Middle East Conference on Biomedical Engineering (MECBME). IEEE, 2011. http://dx.doi.org/10.1109/mecbme.2011.5752155.

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Erskine, R. "ESRA19-0573 1% 2-chloroprocaine for day case unicompartmental knee replacement." In Abstracts of the European Society of Regional Anesthesia, September 11–14, 2019. BMJ Publishing Group Ltd, 2019. http://dx.doi.org/10.1136/rapm-2019-esraabs2019.244.

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Van Den Heever, D. J., C. Scheffer, P. J. Erasmus, and E. M. Dillon. "Development of a patient-specific femoral component for unicompartmental knee replacement." In 2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2009. http://dx.doi.org/10.1109/iembs.2009.5334296.

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Chater-Lea, P., M. Abdallah, and M. Crowley. "LB5 Implementing a standardised technique for adductor canal blockade for unicompartmental knee replacement in a tertiary orthopaedic centre." In ESRA Abstracts, 39th Annual ESRA Congress, 22–25 June 2022. BMJ Publishing Group Ltd, 2022. http://dx.doi.org/10.1136/rapm-2022-esra.524.

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Chater-Lea, P., M. Abdallah, and M. Crowley. "B140 Implementing a standardised technique for adductor canal blockade for unicompartmental knee replacement in a tertiary orthopaedic centre." In ESRA Abstracts, 39th Annual ESRA Congress, 22–25 June 2022. BMJ Publishing Group Ltd, 2022. http://dx.doi.org/10.1136/rapm-2022-esra.215.

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Imran, Ahmed. "Effects of Surgical Placement of Components in Unicompartmental Knee Arthroplasty Evaluated With a Planar Mathematical Model." In ASME 2010 5th Frontiers in Biomedical Devices Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/biomed2010-32018.

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The use of modern technology in knee arthroplasty, like minimally invasive surgery and computer assisted systems, can help in standardization of surgical procedures and improve patient recovery. However, such procedures can affect the surgeon’s ability to properly place and orient the prosthetic components on the bones. In the present study, the effects of surgical placement of components on mechanics of the joint are evaluated. A sagittal plane mathematical model of the knee with unicompartmental replacement is developed. Anatomical data and geometries of the prosthetic components were taken similar to those in literature. Ligaments were represented as bundles of elastic fibers. Net muscle forces were represented along straight lines. The prosthetic components were placed on the bones such that selected fibers in the cruciate ligaments remained nearly isometric and no ligament stretched during flexion. This defined the passive motion of the joint. The effects of external load, muscle activity and variations in component placement or size were superimposed. Component mal-placement or in-appropriate size resulted in stretched/slackened ligaments, influenced the relative positions of bones, and affected joint laxity. The model calculations show general agreement with and explain the experimental/clinical observations reported in literature.
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