Aims. It remains controversial whether
Abstract. Introduction. To investigate the impact medial opening wedge high tibial osteotomy (MOWHTO) has on the progression of patellofemoral OA, patella height and contact pressure within the
Aims. With up to 40% of patients having
Aims. Patellofemoral problems are a common complication of total knee arthroplasty. A high compressive force across the
We present a prospective review of the two-year functional outcome of 37 Avon
Abstract. Introduction. Isolated patellofemoral joint(PFJ) osteoarthritis affects approximately 10% of patients aged over 40 years and treatment remains controversial. Our aim was to evaluate long term functional and radiological outcomes following PFJ arthorplasty with the Femoro Patella Vialli (FPV) prosthesis as this evidence is lacking in literature. Methodology. A retrospective review of prospectively collected PROMS in patients undergoing Patellofemoral arthroplasty. Single centre trial. Between 2004 and 2008, 101 FPV patellofemoral arthroplasties were performed in 80 patients with isolated
Anterior knee pain and/or radiological evidence of degeneration of the
Complications involving the
Aims. The aim of this study was to determine and compare the congruency of the articular surface contact area of the
Introduction. Experimental wear simulation of an all-polymer knee implant has shown an equivalent rate of wear of UHMWPE tibial components against PEEK-OPTIMA™ and cobalt chrome femoral components of a similar initial geometry and surface topography. However, when the patella is resurfaced with an UHMWPE patella button, it is important to also ascertain the wear of the patella. Wear debris from the patella contributes to the total volume of wear debris produced by the implant which should be minimised to reduce the potential for osteolysis and subsequent implant loosening. The aim of this study was to investigate the wear of the
Abstract. Introduction. Isolated patellofemoral osteoarthritis accounts for 10% of knee osteoarthritis. Many of these will not require arthroplasty solutions, but for those who are sufficiently symptomatic,
Introduction: The normal relationships of the
Background. Despite the excellent clinical success of total knee arthroplasty (TAK), controversy remains concerning whether or not to resurface the patella. This has led to a number of randomized controlled trials. Randomized controlled trials constitute the most reliable source of evidence for the evaluation of the efficacy of a potential intervention. But most of these studies include all degree of osteoarthritis of the
Abstract. INTRODUCTION. 10% of patients with knee osteoarthritis (OA) have disease confined to the
Between May 1998 and May 2007 we carried out 50 Avon
One of the most controversial issues in total knee replacement is whether or not to resurface the patella. In order to determine the effects of different designs of femoral component on the conformity of the
We report the results of
Advanced 3D imaging and CT-based navigation have emerged as valuable tools to use in total knee arthroplasty (TKA), for both preoperative planning and the intraoperative execution of different philosophies of alignment. Preoperative planning using CT-based 3D imaging enables more accurate prediction of the size of components, enhancing surgical workflow and optimizing the precision of the positioning of components. Surgeons can assess alignment, osteophytes, and arthritic changes better. These scans provide improved insights into the
We studied the anatomy of the
To assess the clinical outcomes of patients undergoing ACI in the
We report our experience with LCS
Aims. Classifying trochlear dysplasia (TD) is useful to determine the treatment options for patients suffering from patellofemoral instability (PFI). There is no consensus on which classification system is more reliable and reproducible for the purpose of guiding clinicians’ management of PFI. There are also concerns about the validity of the Dejour Classification (DJC), which is the most widely used classification for TD, having only a fair reliability score. The Oswestry-Bristol Classification (OBC) is a recently proposed system of classification of TD, and the authors report a fair-to-good interobserver agreement and good-to-excellent intraobserver agreement in the assessment of TD. The aim of this study was to compare the reliability and reproducibility of these two classifications. Methods. In all, six assessors (four consultants and two registrars) independently evaluated 100 axial MRIs of the
Introduction. Anterior knee pain following total knee arthroplasty continues to be prevalent and may result from abnormal loading of the
The aim of this study was to document the thickness of the
Materials and Methods: The institution’s prospective database of unicompartmental knee replacements was reviewed for all Oxford Phase III Unicompartmental Knee Replacement (Biomet, UK) undertaken from January 2004 to July 2007. This identified a total of 645 procedures undertaken. We included all cases where there was pre-operative skyline radiographs and American Knee Scores, Oxford Knee Score and SF-12 data, in addition to skyline radiographs, OKS and SF-12 data with a minimum of 2 years follow-up. All patients without this baseline and follow-up data were excluded. This provided a total of 196 knees (162 patients). Using Altman’s nomogram, the sample size was calculated to be 85 for a power of 90%, with an α significance level of 0.05. Using this database, digital radiographs were assessed using the institution’s PACS system. Pre-operative and follow-up skyline radiographs following Jones et al’s (1993) patellofemoral scoring system were examined by four assessors utilising Jones’ patellofemoral scoring system. In addition, in cases where
Aims. It is not clear whether anterior knee pain and osteoarthritis
(OA) of the
From September 1995 to March 2003, 15
We investigated the association between the radiological findings and the symptoms arising from the
Aims. Bi-unicondylar arthroplasty (Bi-UKA) is a bone and anterior cruciate ligament (ACL)-preserving alternative to total knee arthroplasty (TKA) when the
Aim: The aim of this study was to asses the accuracy of skyline radiographs in the assessment of the
In some regions in Asia or Arab, there are lifestyles without chair or bed and sitting down on a floor directly, by flexing their knee deeply. However, there are little data about the joint angles, muscle forces or joint loads at such sitting postures or descending to and rising from the posture. In this study, we report the knee joint force and the muscle forces of lower limb at deep squatting and kneeling postures. The model to estimate the forces were constructed as 2D on sagittal plane. Floor reacting force, gravity forces and thigh-calf contact force were considered as external forces. And as the muscle, rectus and vastus femoris, hamstrings, gluteus maximus, gastrocnemius and soleus were taken into the model. The rectus and vastus were connected to the tibia with patella and patella tendon. First the muscle forces were calculated by the moment equilibrium conditions around hip, knee and ankle joint, and then the knee joint force was calculated by the force equilibrium conditions at tibia and patella. For measuring the acting point of the floor reacting force, thigh-calf contact force and joint angles during the objective posture, we performed the experiments. The postures to be subjected were heel-contact squatting (HCS), heel-rise squatting (HRS), kneeling and seiza (Japanese sedentary kneeling), as shown in the Fig.1. The test subjects were ten healthy male, and the average height was 1.71[m], weight was 66.1[kgf] and age was 21.5[years]. The thigh-calf contact force and its acting point were measured by settling the pressure distribution sensor sheet between thigh and calf. Results were normalized by body weight, and shown in Fig.1. The thigh-calf contact force was the largest at the heel-rise squatting posture (1.16BW), and the smallest at heel-contact squatting (0.60BW). The patellofemoral and the tibiofemoral joint forces were shown in the figure. Both forces were the largest at the heel-contact squatting, and were the smallest at the seiza posture. And it might be estimated that the thigh-calf contact force acted anterior when the ankle joint dorsiflexed, and the force was larger when the hip joint extended. The thigh-calf contact force might be decided by not only the knee joint angle but also the hip and ankle joints. As a limitation of this study, we should mention about the effect of the neglected soft tissues. It could be considerable that the compressive internal force of the soft tissues behind a knee joint substance the tibiofemoral force, and then the real tibiofemoral force might be smaller than the calculated values in this study. Then, the tensile force of quadriceps also might be smaller, and then the
Normal function of the
Patellofemoral complications in total knee arthroplasty (TKA) are common. Patellar tracking can be adversely affected by component positioning, soft tissue imbalance and bony deformity. Lateral patellar release rates reported in the literature vary from 6– 40%. Computer assisted surgery has largely been confined to the tibio-femoral component of total knee replacement. However, with recently developed software, it can be used to visualise and quantify patellar tracking and thus guide the precise extent and site of lateral patellar release. The aim of this early study was to define the diagnostic envelope for identification and quantisation of patella maltracking using a current generation patella navigation system. Our previous prospective analysis of 100 patients undergoing primary TKA identified pre-operative radiographic indices that correlate with maltracking of the
Since 1987, autologous chondrocyte implantation (ACI) has been performed in Gothenburg, Sweden in more than 1600 patients. Out of the first 442 patients operated with ACI, 153 (35%) had patella lesions and 91 (21%) had trochlea lesions. Forty two patients (9.5%) had kissing lesions of the
Traditionally, the results of autologous chondrocyte implantation (ACI) in the
Purpose of the study: Kinetic studies of total knee arthroplasty (TKA) in vivo have provided divergent data but have agreed on one point: knee kinetics is abnormal after TKA. Restitution of a normal kinetics is thus the goal to reach to improve functional outcome after TKA. The Journey. ®. TKA is specifically designed to induce automatic medial rotation of the tibia during flexion. This would align the extensor system during flexion and would reduce mediolateral shear forces applied to the
Purpose. Little information is available relating to patient demographics, reasons for failure and types of implants used at time of revision following failure of
Patellofemoral Pain Syndrome is characterized by anterior knee pain during activities such as squatting that is thought to be caused by abnormal patellar motion. However, the causative role has yet to be verified since it is difficult to measure the three-dimensional kinematics of the
The patella is a complex sesamoid bone within the quadriceps enhancing mechanical advantage of the extensor mechanism. Depending on activity, the patella magnifies either force or displacement; behaving as a lever, by redirecting quadriceps force it also acts as a pulley. Aim. We describe and validate a device for obtaining consistent dynamic weight bearing views of the
Introduction. Malrotation of a femoral component is a cause of patellofemoral maltracking after total knee arthroplasty (TKA). We have developed a balanced gap technique in posterior stabilized total knee arthroplasty (PS-TKA) using an original tensor instrument. One of characteristics of this instrument is the ability to measure gaps even if there is a bone defect, because it has two paddles, and we can attach block augmentations. In addition it can measure the gap after a reduction of the patella with an offset mechanism. In the balanced gap technique, the femoral component rotation is decided by a tibial cut surface and ligaments balance using the tensor device. This study investigated retrospectively whether rotational alignment of femoral component rotation influenced
We have used CT to describe the geometry of the patel-lofemoral joint and its relationship to the tibiofemoral joint. 33 CT scans of patients without patellofemoral disease were performed. 3D images were reconstructed and measured using computer software. The flexion axis of the tibiofemoral joint was found as the line connecting the centres of the spheres fitted to posterior femoral condyles. The deepest points on the trochlear groove can be fitted to a circle with radius of 23mm (stdev 4mm) and an rms of 0.3mm. This centre is offset by 21mm (stdev 3mm) at an angle of 68° (stdev 8°) from the line connecting the midpoint between the centres of the femoral condyles and a point in the piriform fossa. On either side of this line, the articular surface of the trochlea can be fitted to spheres of radius 30mm (stdev 6mm) laterally and 27mm (stdev 5mm) and an rms of 0.4mm medially. The centres of the circle and the two spheres fall on a line with an rms of 1.1mm. The anterior and proximal patellar planes could be described as flat surfaces (rms of 0.4 and 0.3mm). The median ridge could be described as a straight line (rms of 0.2mm). The angle between planes was 112° (stdev 5°); the average angle between the proximal plane and the line on the medial ridge was 62° (stdev4°). The length, width and thickness of the patellae were measured at 34.2mm +/−4mm, 44.8mm +/− 4.8mm and 22.4 mm+/− 2.3 mm (table). This investigation has allowed us to characterise the patello-femoral joint geometry which may help identify and explain the aetiology of patello-femoral pathologies. It may have implications for the design of patello-femoral replacements and the rules governing their position.
The Oswestry-Bristol Classification (OBC) was recently described as an MRI-based classification tool for the femoral trochlear. The authors demonstrated better inter- and intraobserver agreement compared to the Dejour classification. As the OBC could potentially provide a very useful MRI-based grading system for trochlear dysplasia, it was the aim to determine the inter- and intraobserver reliability of the classification system from the perspective of the non-founder. Two orthopaedic surgeons independently assessed 50 MRI scans for trochlear dysplasia and classified each according to the OBC. Both observers repeated the assessments after six weeks. The inter- and intraobserver agreement was determined using Cohen’s kappa statistic and S-statistic nominal and linear weights.Aims
Methods
Available AP weight bearing radiographs of the knee taken at 8 months and 5 years postoperatively were examined in a random order twice by each of two surgeons who were blinded to the patient details and length of follow up. The severity of arthritis was graded using the classifications of Ahlback and Altman, giving a measure of arthritis progression.
Patellar tracking in total knee replacements has been extensively studied, but little is known about patellar tracking in isolated patellofemoral replacements. We compared patellar tracking and the position of the patellar groove in the natural knee, followed by implantation of the femoral component of a PFR (patella unresurfaced) and after implantation of the femoral & patellar component of the PFR. Computer navigation was used to track the patella in eight whole lower extremities of four cadavers in the natural knee, in the same knee with the femoral component of the PFR (PFR-P) and with the femoral and patellar component of the PFR (PFR+P, patella resurfaced) (Depuy Sigma PFR). The form and position of the trochlea in the natural knee and the patellar groove of the femoral component was also analysed. Values are means+/−SD, two tailed Student's t-test for paired samples.Introduction
Methods
The purpose of this study was to examine the progression of osteoarthritis (OA) on patella-femoral joint (PFJ) after open wedge high tibial osteotomy (OWHTO) and unicondylar knee arthroplasty (UKA) in correlation with pain and functional outcomes. We conducted a retrospective analysis of 101 knees (89 patients), which received an OWHTO in 42 knees and UKA in 59 knees between 2003 and 2008 with minimum 5-years follow-up. Preoperative and the last follow-up radiologic evaluations were performed on the specific radiographic parameters that reflect the patella and knee alignment. Progressions of OA on PFJ at pre-operation and the last follow up were assessed and compared with modified OA grading system. The patella-femoral (PF) pain and function score were recorded using modified PF scoring system at the last follow up.Purpose
Methods
Aims. Unicompartmental knee arthroplasty (UKA) has become a popular method of treating knee localized osteoarthritis (OA). Additionally, the posterior cruciate ligament (PCL) is essential to maintaining the physiological kinematics and functions of the knee joint. Considering these factors, the purpose of this study was to investigate the biomechanical effects on PCL-deficient knees in medial UKA. Methods. Computational simulations of five subject-specific models were performed for intact and PCL-deficient UKA with tibial slopes. Anteroposterior (AP) kinematics and contact stresses of the patellofemoral (PF) joint and the articular cartilage were evaluated under the deep-knee-bend condition. Results. As compared to intact UKA, there was no significant difference in AP translation in PCL-deficient UKA with a low flexion angle, but AP translation significantly increased in the PCL-deficient UKA with high flexion angles. Additionally, the increased AP translation became decreased as the posterior tibial slope increased. The contact stress in the
In the unstable
Aims. To fully quantify the effect of posterior tibial slope (PTS) angles on joint kinematics and contact mechanics of intact and anterior cruciate ligament-deficient (ACLD) knees during the gait cycle. Methods. In this controlled laboratory study, we developed an original multiscale subject-specific finite element musculoskeletal framework model and integrated it with the tibiofemoral and
Abstract. Objectives. The aim of this study was to develop an in vitro GAG-depleted patella model and assess the biomechanical effects following treatment with a SAP:CS self-assembling hydrogel. Methods. Porcine patellae (4–6 month old) were harvested and subject to 0.1% (w/v) sodium dodecyl sulfate (SDS) washes to remove GAGs from the cartilage. Patellae were GAG depleted and then treated by injection with SAP (∼ 6 mM) and CS (10 mg) in Ringer's solution through a 30G needle. Native, GAG depleted and SAP:CS treated patellae were tested through static indentation testing, using 15g load, 5mm indenter over 1hr period. The degree of deformation of each group was assessed and compared (Mann-Whitney, p<0.05). Native, GAG depleted, sham (saline only) and SAP:CS treated paired patellae and femurs were additionally characterized tribologically through sequential wear testing when undergoing a walking gait profile (n=6 per group). The cartilage surfaces were assessed and compared (Mann-Whitney, p<0.05) using the ICRS scoring system, surface damage was illustrated through the application of Indian ink. Results. Static indentation tests indicated significant increase in indentation deformation of GAG depleted group compared to native group (n=6, p<0.01) and significant reduction in deformation of SAP:CS treated group compared to GAG depleted group (n=6, p<0.05). Sequential wear tests indicated a significant increase in the cartilage damage on the both surfaces of the
Aims. The aim of this study was to evaluate medium-term outcomes and complications of the S-ROM NOILES Rotating Hinge Knee System (DePuy, USA) in revision total knee arthroplasty (rTKA) at a tertiary unit. Methods. A retrospective consecutive study of all patients who underwent a rTKA using this implant from January 2005 to December 2018. Outcome measures included reoperations, revision for any cause, complications, and survivorship. Patients and implant survivorship data were identified through both local hospital electronic databases and linked data from the National Joint Registry/NHS Personal Demographic Service. Kaplan-Meier survival analysis was used at ten years. Results. A total of 89 consecutive patients (89 knees) were included with 47 females (52.8%) and a median age of 74 years (interquartile range 66 to 79). The main indications were aseptic loosening with instability (39.4%; n = 35) and infection (37.1%; n = 33) with the majority of patients managed through two-stage approach. The mean follow-up was 7.4 years (2 to 16). The overall rate of reoperation, for any cause, was 10.1% (n = 9) with a rate of implant revision of 6.7% (n = 6). Only two cases required surgery for patellofemoral complications. Kaplan-Meier implant-survivorship analysis was 93.3% at ten years, using revision for any cause as an endpoint. Conclusion. This implant achieved high ten-year survivorship with a low complication rate, particularly patellofemoral complications. These can be avoided by ensuring central patella tracking and appropriate tension of the
Introduction. The degree of cartilage degeneration assessed intraoperatively may not be sufficient as a criterion for patellar resurfacing in total knee arthroplasty (TKA). However, single-photon emission tomography/computed tomography (SPECT/CT) is useful for detecting osteoarthritic involvement deeper in the subchondral bone. The purpose of the study was to determine whether SPECT/CT reflected the cartilage lesion underneath the patella in patients with end-stage osteoarthritis (OA) and whether clinical outcomes after TKA without patellar resurfacing differed according to the severity of patellofemoral (PF) OA determined by visual assessment and SPECT/CT findings. Methods. This study included 206 knees which underwent TKA. The degree of cartilage degeneration was graded intraoperatively according to the International Cartilage Repair Society grading system. Subjects were classified into four groups according to the degree of bone tracer uptake (BTU) on SPECT/CT in the
There has been debate about the role of unicompartmental knee replacement in the presence of radiologically identifiable degenerative changes of the
Aims. To report mid- to long-term results of Oxford mobile bearing domed lateral unicompartmental knee arthroplasty (UKA), and determine the effect of potential contraindications on outcome. Methods. A total of 325 consecutive domed lateral UKAs undertaken for the recommended indications were included, and their functional and survival outcomes were assessed. The effects of age, weight, activity, and the presence of full-thickness erosions of cartilage in the
Introduction. Instability, loosening, and patellofemoral pain belong to the main causes for revision of total knee arthroplasty (TKA). Currently, the diagnostic pathway requires various diagnostic techniques such as x-rays, CT or SPECT-CT to reveal the original cause for the failed knee prosthesis, but increase radiation exposure and fail to show soft-tissue structures around TKA. There is a growing demand for a diagnostic tool that is able to simultaneously visualize soft tissue structures, bone, and TKA without radiation exposure. MRI is capable of visualising all the structures in the knee although it is still disturbed by susceptibility artefacts caused by the metal implant. Low-field MRI (0.25T) results in less metal artefacts and offers the ability to visualize the knee in weight-bearing condition. Therefore, the aim of this study is to investigate the possibilities of low field MRI to image, the
The biomechanics of the
Introduction. Traditional applied loading of the knee joint in experimental testing of RTKR components is usually confined to replicating the tibiofemoral joint alone. The second joint in the knee, the
We have developed a new tensor for total knee replacements which is designed to assist with soft-tissue balancing throughout the full range of movement with a reduced
Chronic patellofemoral instability can be a disabling condition. Management of patients with this condition has improved owing to our increased knowledge of the functional anatomy of the
The
Summary Statement. This project proves that Patellofemoral (PF) joint degeneration is not a contraindication to medial unicompartmental knee replacement. Introduction. Unicompartmental knee arthroplasty (UKA) is a recognised procedure for treatment of medial compartment osteoarthritis. Patellofemoral (PF) joint degeneration is widely considered to be a contraindication to medial unicompartmental knee replacement. We examined the validity of this preconception using information gathered prospectively on consecutive patients who underwent UKA using the Repicci II® UKA prosthesis for medial compartment osteoarthritis. Methods. We prospectively collected data on 147 consecutive patients who underwent the Repicci II® UKA for medial compartment osteoarthritis. All operations were performed between July 1999 and September 2000 by the same surgeon. The status of the
There have been a large number of studies reporting the knee joint force during level walking, however, the data of during deep knee flexion are scarce, and especially the data about
Introduction. Unicompartmental knee arthroplasty (UKA) is a recognized procedure for treatment of medial compartment osteoarthritis. Patellofemoral (PF) joint degeneration is widely considered to be a contraindication to medial unicompartmental knee replacement. We examined the validity of this preconception using information gathered prospectively on consecutive patients who underwent UKA using the Repicci II® UKA prosthesis for medial compartment osteoarthritis. Methods. We prospectively collected data on 147 consecutive patients who underwent the Repicci II® UKA for medial compartment osteoarthritis. All operations were performed between July 1999 and September 2000 by the same surgeon. The status of the
Introduction. Torsional malalignment syndrome (TMS) is a unique combination of rotational deformities in the lower limb, often leading to severe
Aims. Commonly performed unicompartmental knee arthroplasty (UKA) is not designed for the lateral compartment. Additionally, the anatomical medial and lateral tibial plateaus have asymmetrical geometries, with a slightly dished medial plateau and a convex lateral plateau. Therefore, this study aims to investigate the native knee kinematics with respect to the tibial insert design corresponding to the lateral femoral component. Methods. Subject-specific finite element models were developed with tibiofemoral (TF) and
The contraindications for unicompartmental knee replacement (UKR) remain controversial. The views of many surgeons are based on Kozinn and Scott’s 1989 publication which stated that patients who weighed more than 82 kg, were younger than 60 years, undertook heavy labour, had exposed bone in the
Introduction. Total knee replacement (TKR) is an established and effective surgical procedure in case of advanced osteoarthritis. However, the rate of satisfied patients amounts only to about 75 %. One common cause for unsatisfied patients is the anterior knee pain, which is partially caused by an increase in patellofemoral contact force and abnormal patellar kinematics. Since the malpositioning of the tibial and the femoral component affects the interplay in the
We have examined the differences in clinical outcome of total knee replacement (TKR) with and without patellar resurfacing in a prospective, randomised study of 181 osteoarthritic knees in 142 patients using the Profix total knee system which has a femoral component with features considered to be anatomical and a domed patellar implant. The procedures were carried out between February 1998 and November 2002. A total of 159 TKRs in 142 patients were available for review at a mean of four years (3 to 7). The patients and the clinical evaluator were blinded in this prospective study. Evaluation was undertaken annually by an independent observer using the knee pain scale and the Knee Society clinical rating system. Specific evaluation of anterior knee pain, stair-climbing and rising from a seated to a standing position was also undertaken. No benefit was shown of TKR with patellar resurfacing over that without resurfacing with respect to any of the measured outcomes. In 22 of 73 knees (30.1%) with and 18 of 86 knees (20.9%) without patellar resurfacing there was some degree of anterior knee pain (p = 0.183). No revisions related to the
Introduction: Anterior knee pain is a commonly encountered orthopaedic symptom. Textbooks list a number of clinical symptoms and physical signs that are specific for the
Abstract. Objective. Explore whether high tibial osteotomy (HTO) changes knee contact forces and to explore the relationship between the external knee adduction moment (EKAM) pre and 12 months post HTO. Methods. Three-dimensional gait analysis was performed on 17 patients pre and 12-months post HTO using a modified Cleveland marker-set. Tibiofemoral contact forces were calculated in SIMM. The scaled musculoskeletal model integrated an extended knee model allowing for 6 degrees of freedom in the tibiofemoral and
Introduction. Recurrent patellar dislocation is often reported in bilateral knees in young active individuals. The medial patellofemoral ligament (MPFL) tear is the attributable cause behind many of them and warrants reconstruction of the ligament to stabilize the
Objectives. The aim of the current study was to analyse the effects of posterior cruciate ligament (PCL) deficiency on forces of the posterolateral corner structure and on tibiofemoral (TF) and patellofemoral (PF) contact force under dynamic-loading conditions. Methods. A subject-specific knee model was validated using a passive flexion experiment, electromyography data, muscle activation, and previous experimental studies. The simulation was performed on the musculoskeletal models with and without PCL deficiency using a novel force-dependent kinematics method under gait- and squat-loading conditions, followed by probabilistic analysis for material uncertain to be considered. Results. Comparison of predicted passive flexion, posterior drawer kinematics and muscle activation with experimental measurements showed good agreement. Forces of the posterolateral corner structure, and TF and PF contact forces increased with PCL deficiency under gait- and squat-loading conditions. The rate of increase in PF contact force was the greatest during the squat-loading condition. The TF contact forces increased on both medial and lateral compartments during gait-loading conditions. However, during the squat-loading condition, the medial TF contact force tended to increase, while the lateral TF contact forces decreased. The posterolateral corner structure, which showed the greatest increase in force with deficiency of PCL under both gait- and squat-loading conditions, was the popliteus tendon (PT). Conclusion. PCL deficiency is a factor affecting the variability of force on the PT in dynamic-loading conditions, and it could lead to degeneration of the
Background. Lateral Unicompartmental Knee Arthroplasty (UKA) is a recognised treatment option in the management of lateral Osteoarthritis (OA) of the knee. Whilst there is extensive evidence on the indications and contraindcations in Medial UKA there is limited evidence on this topic in Lateral UKA. The aim of this study was to assess our experience of mobile lateral UKR and to look specifically at the effect of Contraindications on the outcome. Method. A total of 325 consecutive domed lateral UKAs undertaken for the recommended indications were included, and their functional and survival outcomes were assessed. The effects of age, weight, activity, and presence of full- thickness erosions of cartilage in the
Background. Secondary osteonecrosis of the knee (SOK) generally occurs in relatively young patients in their working years; at advanced stages of SOK, the only viable surgical option is total knee arthroplasty (TKA). We conducted a retrospective study to investigate implant survivorship, clinical and radiographic outcomes, and complications of cemented TKA with/without patellar resurfacing for SOK. Methods. Thirty-eight cemented TKAs in 27 patients with non-traumatic SOK with a mean age 43 years (range 17–65) were retrospectively reviewed. Twenty-one patients (78%) were female. Mean body mass index was 31 kg/m. 2. (range 20–48); 11 patients (41%) received bilateral TKAs. Twenty patients (74%) had a history of corticosteroid use and 18% had a history of alcohol abuse. Patellar osteonecrosis was coincidentally found in six knees (16%), all of which had no anterior knee pain and had no
Introduction. Persistent anterior knee pain, subluxation or dislocation of the patella as well as early aseptic loosening and increased polyethylene wear of the patella implant are common clinical problems after total knee arthroplasty (TKA) which are associated with the
Background. Flexion-extension gap balancing is recognized as an essential part of total knee arthroplasty (TKA). The gap is often evaluated using spacer blocks, laminar spreader, or tensor device. The evaluation of gap balancing with the patella in the reduced position is more physiological and reproducible than with patellofemoral (PF) joint everted. However, in the knee with a reduced
Introduction. A large number of total knee arthroplasty (TKA) patients, particularly in Japan, India and the Middle East, exhibit anatomy with substantial proximal tibial torsion. Alignment of the tibial components with the standard anterior-posterior (A-P) axis of the tibia can result in excessive external rotation of the tibial components with respect to femoral component alignment. This in turn influences patellofemoral (PF) mechanics and forces required by the extensor mechanism. The purpose of the current study was to determine if a rotating-platform (RP) TKA design with an anatomic patellar component reduced compromise to the patellar tendon, quadriceps muscles and PF mechanics when compared to a fixed-bearing (FB) design with a standard dome-shaped patellar component. Methods. A dynamic three-dimensional finite element model of the knee joint was developed and used to simulate a deep knee bend in a patient with excessive external tibial torsion (Figure 1). Detailed description of the model has been previously published [1]. The model included femur, tibia and patellar bones, TKA components, patellar ligament, quadriceps muscles, PF ligaments, and nine primary ligaments spanning the TF joint. The model was virtually implanted with two contemporary TKA designs; a FB design with domed patella, and a RP design with anatomic patella. The FB design was implanted in two different alignment conditions; alignment to the tibial A-P axis, and optimal alignment for bone coverage. Four different loading conditions (varying internal-external (I-E) torque and A-P force) were applied to the model to simulate physiological loads during a deep knee bend. Quadriceps muscle force, patellar tendon force, and PF and TF joint forces were compared between designs. Results. The RP design demonstrated consistently lower medial-lateral (M-L) force at the
The influence of soft tissue balance in mobile-bearing posterior-stabilized (PS) total knee arthroplasty (TKA) on the patellofemoral (PF) joint was investigated in thirty varus-type osteoarthritis patients. Intraoperative soft tissue balance including joint component gap and varus/valgus ligament balance and the medial/lateral patellar pressure were measured throughout the range of motion after the femoral component placement and the
Although complications associated with patello-femoral (PF) joint account for up to 50% of total knee replacement (TKR) revision procedures (Lee), the
Important factors affecting quality of life (QOL) after total knee arthroplasty (TKA) include postoperative knee kinematics and geometry, influenced by implant design and placement (Matsuda 2001; Nishikawa 2013; Noble 2005). Although specific design factors and their effect on kinematics or QOL have been investigated previously, the inter-relationships between preop-postop changes in kinematics, geometry and the resulting QOL have not been studied to our knowledge. These are essential to understand the interplay between the different factors, and to determine which factors manufacturers and surgeons should focus on when designing and implanting knee prostheses. In addition, the majority of TKA studies focus on the tibiofemoral (TF) joint, although the patellofemoral (PF) joint is routinely the source of postop complications; the
Purpose: Our purpose was to study the 10-year results of a proximal soft-tissue procedure combined with a Lateral Patellar Facetectomy technique for an isolated osteoarthritis of
The aim of this study was to assess the benefit and durability of isolated lateral release for advanced osteoarthritis of the lateral facet of the
Total knee arthroplasty (TKA) has produced excellent results, but many surgeons are hesitant to perform TKA in younger patients with isolated patellofemoral arthritis. In properly selected patients, patellofemoral arthroplasty (PFA) is an effective procedure with good long-term results. Contemporary PFA prostheses have eliminated many of the patellar maltracking problems associated with older designs, and short-term results, as described here, are encouraging. Long-term outcome and prospective trials comparing TKA to PFA are needed. Incidence. Isolated patellofemoral arthritis occurs in as many as 11% of men and 24% of women older than age 55 years with symptomatic osteoarthritis (OA) of the knee; Isolated patellofemoral arthritis found in 9.2% of patients older than age 40 years; 7% to 19% of patients experience residual anterior knee pain when TKA is done for isolated patellofemoral arthritis. Imaging. Weight bearing AP radiographs as supine radiographs can underestimate the extent of tibiofemoral arthritis; Midflexion posteroanterior radiographs to rule out posterior condylar wear; Lateral radiographs to identify the presence or absence of patella alta or baja; Axial radiographs identify the presence of trochlear dysplasia, patellar tilt or subluxation, and extent of patellofemoral arthritis; Magnetic resonance imaging and arthroscopic photographs should be reviewed if available. Indications. Osteoarthritis limited to the
The effects of advancement of the tibial tuberosity by inserting bony wedges was studied on cadaveric specimens of the knee. The geometry, the contact areas and the forces acting on the
Background. More and more patients with end-stage knee OA are treated with total knee replacements (TKR). A modern TKR (Persona PS system, Zimmer Inc.) was designed with the hope to improve fit by providing additional sizing options on the femur and tibia. To date, there is very little information regarding the knee strength and knee mechanics during gait after the TKR. Furthermore, as a great percentage of knee OA patients have OA limited in one knee compartment and in the
Introduction. Patellar resurfacing affects patellofemoral (PF) kinematics, contact mechanics, and loading on the patellar bone. Patients with total knee arthroplasty (TKA) often exhibit adaptations in movement patterns that may be linked to quadriceps deficiency and the mechanics of the reconstructed knee [1]. Previous comparisons of PF kinematics between dome and anatomic resurfacing have revealed differences in patellar sagittal plane flexion [2], but further investigation of
Introduction. Complications related to the
Multiple studies have shown that the symptomatology of knee osteoarthritis weakly correlate to radiographic severity of disease. Current literature however does not have much in the way of comparing functional outcomes of those with OA knees with radiographic severity. Our objective was to compare radiographic measurements of OA knees with self-reported functional outcomes and determine if radiographic severity of OA knees correlated with loss of functional ability. A retrospective review of prospectively collected registry data of 305 patients with osteoarthritis of the knee was collected. The patient's x-rays were reviewed, and radiographic measurements were taken to include medial, lateral and
Introduction. The assumption that symmetric extension-flexion gaps improve the femoral condyle lift-off phenomenon and the
The August 2024 Trauma Roundup360 looks at: Does topical vancomycin prevent fracture-related infections in closed fractures undergoing open reduction and internal fixation? A randomized controlled trial; Is postoperative splinting advantageous after upper limb fracture surgery?; Does suprapatellar nailing resolve knee pain?; Locking versus non-locking plate fixation in comminuted talar neck fractures: a biomechanical study using cadaveric specimens; Revolutionizing recovery metrics: PROMIS versus SMFA in orthopaedic trauma care; Dorsal hook plating of patella fractures: reliable fixation and satisfactory outcomes; The impact of obesity on subtrochanteric femur fracture outcomes; Low-dose NSAIDs (ketorolac) and cytokine modulation in orthopaedic polytrauma: a detailed analysis.
To assess the incidence of radiological lateral osteoarthritis (OA) at 15 years after medial unicompartmental knee arthroplasty (UKA) and assess the relationship of lateral OA with symptoms and patient characteristics. Cemented Phase 3 medial Oxford UKA implanted by two surgeons since 1998 for the recommended indications were prospectively followed. A 15-year cumulative revision rate for lateral OA of 5% for this series was previously reported. A total of 163 unrevised knees with 15-year (SD 1) anterior-posterior knee radiographs were studied. Lateral joint space width (JSWL) was measured and severity of lateral OA was classified as: nil/mild, moderate, and severe. Preoperative and 15-year Oxford Knee Scores (OKS) and American Knee Society Scores were determined. The effect of age, sex, BMI, and intraoperative findings was analyzed. Statistical analysis included one-way analysis of variance and Kruskal-Wallis H test, with significance set at 5%.Aims
Methods
Modifiable factors contributing to stiffness include alignment, implant size, implant position and rotation, and soft tissue tightness or laxity. Less modifiable factors include genetics as in predisposition to inflammation and fibrosis, aberrations in perception and experience of emotional pain, and preoperative range of motion. We reviewed 559 knees undergoing revision between 2007 and 2014, selecting out patients with a diagnosis of stiffness and greater than one-year follow-up. Stiffness was defined as greater than 15 degrees of flexion contracture or less than 75 degrees of flexion or less than 90 degrees of active motion and a chief complaint of limited motion and pain. Radiographic analysis used a set of matched controls with greater than 90 degrees and full extension prior to surgery and were further matched by age, gender, BMI. Flexion contracture changed from an average of 9.7 to an average of 2.3 degrees, flexion changed from an average of 81 to an average of 94 degrees, active motion changed from an average of 72 to an average of 92 degrees, pain scores improved from 44 to 72 points, and Knee Society function scores improved from an average of 49 to an average of 70 points. There were four failures for stiffness, two knees underwent additional manipulation, gaining an average of 10 degrees; and two knees were revised. Radiographic analysis demonstrated stiffness to be strongly correlated to anterior condylar offset ratio and to patellar displacement by multivariant regression analysis, suggesting that overstuffing the
Recurrent patella dislocation is a well-recognized complication after primary dislocation of the
Although cartilage repair has been around since the time of open Pridie drilling, clinical outcomes for newer techniques such as arthroscopic debridement, microfracture (MFX), osteochondral autograft transfers (OATS), osteochondral allograft transplantation and Autologous Chondrocyte Implantation (ACI) are still finding their place in treating injured knees. Early mechanical symptoms are best managed by a gentle arthroscopic debridement of loose articular flaps. This allows the surgeon to assess the defect size, location in the tibio-femoral or
Introduction. Knee arthroplasty is an effective intervention for painful arthritis when conservative measures have failed. Despite recent advances in component design and implantation techniques, a significant proportion of patients experience problems relating to the patella-femoral joint (PFJ). Detailed knowledge of the shape and orientation of the normal and replaced femoral trochlea groove is critical when considering potential causes of anterior knee pain. Furthermore, to date it has proved difficult to establish a diagnosis due to shortcomings in current imaging techniques for obtaining satisfactory coronal plane motion data of the patella in the replaced knee. The aim of this study was to correlate the trochlea shape of normal and replaced knees with corresponding coronal plane PFJ kinematic data. Method. Bony and cartilagenous trochlea geometries from 3T MRI scans of 20 normal healthy volunteers were compared with both anatomical and standard total knee replacements (TKR) and
Enhanced appreciation of normal knee kinematics and the inability to replicate these in the replaced total knee has led to increased enthusiasm for partial knee arthroplasty by some. These arthroplasties more closely replicate normal kinematics since they inherently preserve the anterior cruciate ligament (ACL). Indications for medial UKA are: anteromedial osteoarthritis with an intact ACL, posterior cruciate ligament, and medial collateral ligament (MCL), full thickness cartilage loss, and correctable deformity demonstrated radiographically with valgus stress view; full thickness cartilage laterally with no central ulcer; <15 degrees of flexion contracture, < 15 degrees varus and > 90 degrees flexion. The state of the
Introduction. MERA Quest Knee System (Quest Knee) is a posterior cruciate ligament–retaining prosthesis considering the anatomical features and lifestyles of the Japanese. As for the anatomical features, we reduced the size of prosthesis and set a smaller interval of sizes because Japanese knees are smaller and flatter than those of Caucasians. As for the lifestyles, we evaluated in vivo patellar tracking during deep knee flexion and the condylar geometry in the axial plane of magnetic resonance imaging. It was found that the patella sank deeply into the intercondylar notch and that the articular surface of the lateral condyle began to curve steeply. We adopted this shape and engraved the lateral condyle deep to reduce the pressure of the