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BACKGROUND: Most of the domestic and foreign literatures reported the mid-term and long-term effects of the unicompartmental knee arthroplasty of the mobile bearing, but few reported the mid-term and long-term clinical effects of the unicompartmental knee arthroplasty of the fixed bearing. Simultaneously, most of the studies did not analyze the knee function recovery and the lower limb force line change at different time points after the fixed bearing unicompartmental knee arthroplasty, and also ignored the follow-up of the patients’ self-feeling after the unicompartmental knee arthroplasty. OBJECTIVE: To explore the mid-term clinical effect of fixed bearing unicompartmental knee arthroplasty in the treatment of medial compartment osteoarthritis of knee joint and to observe the change of force line of lower limbs. METHODS: From January 2014 to January 2015, a retrospective analysis was made of the data of 66 patients diagnosed as osteoarthritis of the medial compartment of the knee in the Department of Arthritis, Foshan Hospital of Traditional Chinese Medicine. According to the inclusion and exclusion criteria, 66 patients were included, including 18 males and 48 females, aged (62.36±16.33) years. The American Knee Society knee score and the hospital for special surgery knee score were used to assess the knee function before and 1, 3 and 5 years after the operation. Visual analogue scale score was utilized to evaluate the severity of knee. Forgotten joint score was used to assess the subjective feeling of prosthesis after unicompartmental knee arthroplasty. Hip-knee-ankle angle and tibiofemoral angle were measured using X-ray films before treatment and at follow-up to evaluate the force line of weight-bearing lower limbs. RESULTS AND CONCLUSION: (1) The postoperative follow-up time was 5-6 years, averagely 5.5 years. The incision healed in the first stage. There was no early complication such as joint infection or lower extremity deep vein thrombosis, and there was no prosthesis loosening, dislocation or other diseases of the contralateral compartment and patellofemoral joint. (2) The American Knee Society knee score clinical score, American Knee Society knee score function score, hospital for special surgery knee score, knee motion range and visual analogue scale score were lower at 1, 3 and 5 years after operation than those before treatment (P < 0.05). The American Knee Society knee score clinical score, American Knee Society knee score function score, knee motion range and visual analogue scale score at 3 and 5 years after operation were significantly lower than those at 1 year after operation (P < 0.05). There was no significant difference in American Knee Society knee score clinical score, American Knee Society knee score function score, knee motion range and visual analogue scale score between 3 and 5 years postoperatively (P > 0.05). (3) Forgotten joint score was higher at 3 and 5 years after treatment than that at 1 year after treatment (P < 0.05); and there was no significant difference between 3 and 5 years postoperatively (P > 0.05). (4) Hip-knee-ankle angle and tibiofemoral angle were significantly improved after treatment in all patients compared with those before treatment (P < 0.05). There was no significant difference in hip-knee-ankle angle and tibiofemoral angle at 1, 3 and 5 years postoperatively (P > 0.05). (5) The results show that the mid-term clinical effect of unicompartmental knee arthroplasty with fixed bearing is satisfactory, and the degree of self-prosthesis is high. After treatment, the force line of lower limbs was improved, and there was no significant change in the 5-year follow-up. [ABSTRACT FROM AUTHOR]

Introduction: We aimed to explore the risk factors for periprosthetic joint infection (PJI) after primary artificial hip and knee joint replacements by performing a case-control study. Methodology: The clinical data of patients receiving primary hip and knee joint replacements were retrospectively analyzed. The case group included 96 patients who suffered from PJI, comprising 42 cases of hip joint replacement and 54 cases of knee joint replacement. Another 192 patients who received joint replacement at the ratio of 1:2 in the same period and did not suffer from PJI were selected as the control group. Differences between the two groups were compared in regard to etiology, pathogen, blood type, urine culture, body mass index (BMI), surgical time, intraoperative blood loss, postoperative 1st day and total drainage volumes, length of hospitalization stay, and history of surgery at the affected sites. Results: Gram-positive bacteria were the main pathogens for PJI. The most common infection after hip joint replacement was caused by Staphylococcus epidermidis, which accounted for 38.10%, while Staphylococcus aureus was mainly responsible for the infection of knee joint (40.74%). High BMI, long surgical time, large postoperative drainage volume, long hospitalization stay, history of surgery at incisions, previous use of immunosuppressants, preoperative hypoproteinemia and superficial infection were independent risk factors (p < 0.05). Conclusions: PJI after primary replacement was mainly caused by gram-positive bacteria, and patients with high BMI, long surgical time, large postoperative drainage volume, long hospitalization stay, history of surgery at incisions, previous use of immunosuppressants, preoperative hypoproteinemia and superficial infection were more vulnerable. [ABSTRACT FROM AUTHOR]

BACKGROUND: Three-dimensional (3D) printing technology is a new rapid prototyping technology, which has been initially applied in orthopedics, especially in the clinical application of hip replacement surgery. OBJECTIVE: To summarize the application status, existing problems and future development direction of 3D printing technology in hip arthroplasty. METHODS: The relevant articles published between January 2000 and March 2019 were retrieved from PubMed, CNKI and WanFang databases. The keywords were "3D printing, rapid prototyping, additive manufacturing, computer aided, computer-assisted, hip, hip replacement, hip arthroplasty, revision hip arthroplasty" in English and Chinese, respectively. Initially, 1833 articles were retrieved, and finally 105 eligible articles were included for result analysis in accordance with the inclusion and exclusion criteria. RESULTS AND CONCLUSION: (1) In the clinical application of hip replacement surgery, 3D printing technology is mainly used to make anatomical models for clinical teaching or preoperative plan, patient-specific surgical guides, customized implants or prostheses. (2) The advantages of 3D printing technology can make up for the deficiency of traditional treatment, and n can help to optimize the surgical plan, shorten the operation time, decrease the bleeding, reduce postoperative complications, improve the accuracy of surgery and clinical results. (3) Individualized treatment with 3D printing technology will become a new direction in hip arthroplasty. [ABSTRACT FROM AUTHOR]

The INBONE total ankle replacement has been in use since 2005. Although studies are not available regarding its success, it is increasingly being used because of its unique design. This design features a wide modular tibial stem onto which additional components can be added to increase its length and a talar component with a modular stem. A leg holder is used with the aid of fluoroscopy in attaining alignment during insertion. The design helps the surgeon deal with severe deformity, tibial bone loss, distal tibia infarction and revision total ankle arthroplasty. This article details the techniques used for its insertion. [ABSTRACT FROM AUTHOR]

Five patients with rheumatoid arthritis or osteoarthrosis of the wrist joint were followed up for 15 (14-17) years after wrist-joint arthroplasty with semiconstrained artificial joint mechanisms that had been anchored to bone using the osseointegration principle. They were fixed by one titanium screw introduced into the radius, and two or more titanium screws introduced distally into the metacarpal bones. In four cases a screw was also introduced into the ulna thereby constituting one component in a distal radio-ulnar (DRU) joint mechanism. The titanium screw introduced into the radius and the distal metacarpal screws osseointegrated in all cases. In three cases the mechanism of the wrist joint or parts of it were replaced with new components that could be attached to the screws that were already osseointegrated. We conclude that wrist joint prostheses can be anchored to the surrounding bone using osseointegration and that they remain fixed for at least 15 years. The principle allows replacement of the joint mechanism, if needed, with maintenance of the osseointegrated anchoring elements. [ABSTRACT FROM AUTHOR]

Seven men mean age 37 years (range 24-45) who had destroyed metacarpophalangeal joints as a result of pyogenic infection underwent reconstruction of the joint with osseointegrated silicone implants. The interval from infection to reconstruction varied from 5 months to 13 years. At mean follow-up 10 (8-12) years postoperatively the titanium fixtures were all well osseointegrated. The silicone spacer had fractured in one case. The extension lag was 16 (10-20)° and the range of movement (ROM) 34 (30-40)°. Our data confirm previous observations about the successful long-term osseointegration of titanium fixtures used for the attachment of joint prostheses in the hands of patients with rheumatoid arthritis or osteoarthritis. We conclude that titanium fixtures can be used successfully to fix joint mechanisms for reconstruction of small joints after pyogenous arthritis of the hand and can be used for fixation of joint mechanisms in such cases. [ABSTRACT FROM AUTHOR]

Osseointegrated proximal interphalangeal joint prostheses with a replacable joint spacer were used in 25 joints in 19 patients (five men and 14 women) aged 45 (16-67) years. Indications for surgery were post-traumatic arthrosis (nine joints in eight patients), primary osteoarthrosis (10 joints in eight patients), and rheumatoid arthritis (six joints in three patients). A silicone joint spacer was attached to titanium fixtures by short titanium stems that extended from the spacer and fitted into a central canal in the screws. The arthroplasty was done in one stage, which included resection of the joint followed by grafting of marrow and cancellous bone from the iliac crest into adjacent medullary cavities before insertion of the titanium fixture. Follow up at 8.5 (5-11) years showed that 47 out of 50 fixtures (94%) had successfully osseointegrated while 17 of 25 joint spacers (68%) had fractured. However, because of the design of the prostheses fractured joint spacers could easily be replaced and a new spacer could be connected to already osseointegrated screws. The joint spacer was replaced in 11 fingers once or several times. Range of movement (ROM) in the whole series (four fusions excluded) was 41 (0-85)° with an extension defect of 15 (0-55)°. In eight joints with permanently intact joint spacers the ROM was 39 (0-60)° with extension defects of 16 (0-40)°. In six joints in which the spacer was replaced once the ROM was 43 (0-85)° with an extension defect of 16 (0-55)°. Our data confirm good long-term osseointegration of titanium fixtures and that a joint spacer, if needed, can be replaced by a new spacer that can be attached to already osseointegrated screws without jeopardising the ROM. [ABSTRACT FROM AUTHOR]

Hip joint replacements using highly cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) as a bearing material offer an effective treatment to arthritis. However, the bearing wear may affect the longevity of implants which requires more rigorous investigations. UHMWPE wear is highly dependent on cross-shear (CS) as a result of the multidirectional motion of bearings. Previously, a wear model has been developed with the potential to provide accurate simulation, of which the wear was determined as an exponential function of sliding distance with CS at the crossing angle of 90°, and the effect of CS for an arbitrary angle was quantified to be proportional to the perpendicular component of sliding distance. In the present study, the wear was proposed as the exponential function of frictional work. In particular, contact pressure was incorporated into the calculation of frictional work by considering that the friction coefficient is a function of contact pressure. In addition, the CS quantification for arbitrary crossing angles was considered by coupling the sliding distance and frictional force. The computational formulations of the present and previous models were compared by applying the models to a 36 mm diameter metal-on-polyethylene total hip prosthesis with highly cross-linked UHMWPE at 5 Mrad irradiation under simulated walking conditions. The simulation was also validated against the published results of hip simulator tests with respect to the influence of motion/loading condition on wear. The study showed markedly improved computational predictions with wear rate discrepancies in the range of 8–25% for two kinematic conditions either with the fixed or with varying direction of load. The results show the important role of both the frictional work and contact pressure, and they should be both incorporated appropriately to enhance the computational modelling. • Wear of highly cross-linked UHMWPE has been modelled to improve understanding of wear mechanism for hip joint prostheses. • A new model has been theoretically introduced and validated against hip joint simulator tests, based on a previous method. • The wear model has been improved for quantifying the cross-shear wear incorporating frictional work and contact pressure. • Both frictional work and contact pressure should be formulated appropriately to enhance computational modelling. [ABSTRACT FROM AUTHOR]