There are several methods for evaluating stability of the joint during total knee replacement (TKR). Activities of daily living demand mechanical loading to the knee joint, not only in full extension, but also in mid-flexion. The purpose of this study was to compare the varus-valgus stability throughout flexion in knees treated with either cruciate-retaining or posterior-stabilised TKR, using an intra-operative navigation technique. A total of 34 knees underwent TKR with computer navigation, during which the investigator applied a maximum varus-valgus stress to the knee while steadily moving the leg from full extension to flexion both before and after prosthetic implantation. The femorotibial angle was measured simultaneously by the navigation system at every 10° throughout the range of movement. It was found that posterior-stabilised knees had more varus-valgus laxity than cruciate-retaining knees at all angles examined, and the differences were statistically significant at 10° (p = 0.0093), 20° (p = 0.0098) and 30° of flexion (p = 0.0252). Cite this article: Bone Joint J 2013;95-B:493–7

Objectives. Little biomechanical information is available about kinematically aligned (KA) total knee arthroplasty (TKA). The purpose of this study was to simulate the kinematics and kinetics after KA TKA and mechanically aligned (MA) TKA with four different limb alignments. Materials and Methods. Bone models were constructed from one volunteer (normal) and three patients with three different knee deformities (slight, moderate and severe varus). A dynamic musculoskeletal modelling system was used to analyse the kinematics and the tibiofemoral contact force. The contact stress on the tibial insert, and the stress to the resection surface and medial tibial cortex were examined by using finite element analysis. Results. In all bone models, posterior translation on the lateral side and external rotation in the KA TKA models were greater than in the MA TKA models. The tibiofemoral force at the medial side was increased in the moderate and severe varus models with KA TKA. In the severe varus model with KA TKA, the contact stress on the tibial insert and the stress to the resection surface and to the medial tibial cortex were increased by 41.5%, 32.2% and 53.7%, respectively, compared with MA TKA, and the bone strain at the medial side was highest among all models. Conclusion. Near normal kinematics was observed in KA TKA. However, KA TKA increased the contact force, stress and bone strain at the medial side for moderate and severe varus knee models. The application of KA TKA for severe varus knees may be inadequate. Cite this article: S. Nakamura, Y. Tian, Y. Tanaka, S. Kuriyama, H. Ito, M. Furu, S. Matsuda. The effects of kinematically aligned total knee arthroplasty on stress at the medial tibia: A case study for varus knee. Bone Joint Res 2017;6:43–51. DOI: 10.1302/2046-3758.61.BJR-2016-0090.R1

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This study aimed to evaluate calprotectin in synovial fluid for diagnosing chronic prosthetic joint infection (PJI) .

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The Fassier Duval (FD) rod is a third-generation telescopic implant for children with osteogenesis imperfecta (OI). Threaded fixation enables proximal insertion without opening the knee or ankle joint. We have reviewed our combined two-centre experience with this implant.

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The aim of this study was to systematically review the literature for evidence of the effect of a high-fat diet (HFD) on the onset or progression of osteoarthritis (OA) in mice.

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This study aims to evaluate a new home medical stretching device called the Self Treatment Assisted Knee (STAK) tool to treat knee arthrofibrosis.

Sixty-nine patients with congenital abnormality of the femur were reviewed. Their manifestation of femoral dysplasia ranged from an intact femur approximately 60 per cent of the length of the normal leg to a subtotal absence of the femur in which only the femoral condyles remained, often with a congenital fusion of the knee joint. Two groups were defined: Group I consisted of those with congenital hypoplastic femur in which the hip and knee could be made functional and where, in some patients at least, leg equalisation was possible; Group II consisted of those with true proximal focal femoral deficiency where the hip joint was never normal and the knee joint was always useless. The patients in each group were examined and evaluated with respect to clinical signs, surgical procedures performed, and prosthetic requirements and function. A protocol of treatment for both groups is suggested

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We report the natural course of Baker’s cysts following total knee arthroplasty (TKA) at short- and mid-term follow-up.

1. Attention is drawn to the powers of resistance of the growing ends of bones in suppurative pyogenic arthritis of the knee and hip in infancy. 2. It is emphasised that a translucent zone in the radiograph does not necessarily mean that this part of the bone, epiphysial cartilage or plate is destroyed. 3. Diagnostic criteria are described to confirm that cartilage or decalcified bone has survived the infection in the knee joint. 4. The prognosis for the knee joint is discussed. 5. The hip joint presents greater difficulties in diagnosis and greater issues are at stake. It is recommended therefore that the hip joint be manipulated or explored if the radiograph and the physical signs suggest that destruction of the joint has either caused dislocation or has so damaged it that dislocation is likely to occur in the future. In favourable cases stability may be restored to the hip. In the others a diagnosis of irreparable destruction is established and the surgeon is satisfied that an opportunity to help the patient has not been lost

1. The movements of flexion and extension at the knee joint take place above the menisci; the movements of rotation take place below the menisci. 2. The popliteus muscle consists of two halves, one being attached by tendon to the femur, the other by aponeurosis to the lateral meniscus. The action of the muscle is to rotate the knee and retract the posterior arch of the lateral meniscus. The flexing action of the muscle is quite negligible. 3. The effects of rotation of the knee joint on the two menisci are dissimilar. The medial meniscus is distorted during rotation; its horns move with the tibia, but the intervening arch moves with the femur, and the distortion renders it liable to injury during rotation. The lateral meniscus does not become distorted during rotation; it follows the lateral condyle of the femur by reason of the attachments of the ligaments of Humphry and Wrisberg and the popliteus muscle. It is thus relatively immune from injury daring rotation

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Appropriate acetabular component placement has been proposed for prevention of postoperative dislocation in total hip arthroplasty (THA). Manual placements often cause outliers in spite of attempts to insert the component within the intended safe zone; therefore, some surgeons routinely evaluate intraoperative pelvic radiographs to exclude excessive acetabular component malposition. However, their evaluation is often ambiguous in case of the tilted or rotated pelvic position. The purpose of this study was to develop the computational analysis to digitalize the acetabular component orientation regardless of the pelvic tilt or rotation.

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The aim of this study was to evaluate the performance of metagenomic next-generation sequencing (mNGS) in detecting pathogens from synovial fluid of prosthetic joint infection (PJI) patients.

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The purpose of this study was to determine whether intracellular Staphylococcus aureus is associated with recurrent infection in a rat model of open fracture.

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The use of technology to assess balance and alignment during total knee surgery can provide an overload of numerical data to the surgeon. Meanwhile, this quantification holds the potential to clarify and guide the surgeon through the surgical decision process when selecting the appropriate bone recut or soft tissue adjustment when balancing a total knee. Therefore, this paper evaluates the potential of deploying supervised machine learning (ML) models to select a surgical correction based on patient-specific intra-operative assessments.

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The primary aim of the study was to compare the knee-specific functional outcome of robotic unicompartmental knee arthroplasty (rUKA) with manual total knee arthroplasty (mTKA) for the management of isolated medial compartment osteoarthritis. Secondary aims were to compare length of hospital stay, general health improvement, and satisfaction between rUKA and mTKA.

1. Pain and pressure sensibility has been studied in the fibrous articular ligament and synovial membrane of the knee joint in normal human subjects and in patients subjected to arthrotomy under local anaesthesia. 2. The fibrous ligament was found to be a highly sensitive structure, containing many spots which give rise to sensations of pain or pressure when stimulated mechanically or chemically. Synovial membrane was found to be a relatively insensitive structure which only occasionally contains pain-sensitive spots. 3. Histological examination of articular capsule from the knee joints of normal and sympathectomised cats shows that articular ligaments have a rich nerve plexus and a variety of specialised and unspecialised nerve endings, most of which are somatic in origin. Synovial membrane contains a more delicate nerve network and also a variety of nerve endings, the majority of which are autonomic in origin. But a substantial number of somatic nerves enter the synovial membrane, some of which terminate in nerve loops, globular endings or simple unspecialised endings. 4. Histological examination of normal human articular capsule shows that its innervation closely resembles that of the cat, but no sympathectomised human material was examined. 5. The bearing of these findings on the symptomatology of joint disease is discussed briefly

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Femoral revision component subsidence has been identified as predicting early failure in revision hip surgery. This comparative cohort study assessed the potential risk factors of subsidence in two commonly used femoral implant designs.

The outcome of arthroscopic medial release of 255 knees in 173 patients for varying grades of osteoarthritis involving the medial compartment is reported. All operations were performed by a single surgeon between January 2001 and May 2003. The Knee Society score for pain and the patient’s subjective satisfaction were used for the outcome evaluation. Overall, satisfactory outcome was reported for 197 knees (77.3%) and the mean Knee Society score for pain improved from 17.6 (95% confidence interval, 16.7 to 18.5), pre-operatively to 39.4 (95% confidence interval, 37.9 to 41.1) (p < 0.001). There were minor manageable complications of persistent effusion in 16 knees and prolonged wound discomfort in 11. In total, 15 of the 21 knees with poor results were converted to total knee replacements and two other patients (three knees) were offered this option after a mean period of 16 months. Based on these observations arthroscopic medial release is an effective treatment for osteoarthritis of the medial compartment of the knee joint and can be expected to reduce the pain in the majority of patients for at least four years post-operatively

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This study aims to determine the proportion of patients with end-stage knee osteoarthritis (OA) possibly suitable for partial (PKA) or combined partial knee arthroplasty (CPKA) according to patterns of full-thickness cartilage loss and anterior cruciate ligament (ACL) status.