Outcomes of Surface Replacement Arthroplasty in Metacarpophalangeal Joints Affected by Noninflammatory Arthritis

Background The purpose of this study was to investigate the outcomes of surface replacement arthroplasty (SRA) for noninflammatory arthritis of the metacarpophalangeal (MCP) joint. Methods Records from 20 SRAs performed between 1995 and 2017 in 17 patients with noninflammatory arthritis affecting the MCP joint were retrospectively reviewed. The mean follow up was 6.6 years. Results Three arthroplasties (15%) underwent 4 revision operations. The 2-, 5-, 10-, and 15-year rates of survival from surface replacement implant revision were 90%, 90%, 79%, and 79%, respectively. Major complications occurring in revised joints included arthrodesis (n = 1) and amputation (n = 1). The overall reoperation rate was 35%. The 2-, 5-, 10-, and 15-year rates of overall reoperation-free survival were 75%, 69%, 60%, and 60%, respectively. Conclusions Pain ratings and MCP arc of motion significantly improved following arthroplasty. Metacarpophalangeal SRA for noninflammatory arthritis can improve arc of motion and pain. Revision is uncommon; however, 1 in 3 joints requires reoperation.

Structured argumentation dynamics

This paper develops a logical theory that unifies all three standard types of argumentative attack in AI, namely rebutting, undercutting and undermining attacks. We build on default justification logic that already represents undercutting and rebutting attacks, and we add undermining attacks. Intuitively, undermining does not target default inference, as undercutting, or default conclusion, as rebutting, but rather attacks an argument’s premise as a starting point for default reasoning. In default justification logic, reasoning starts from a set of premises, which is then extended by conclusions that hold by default. We argue that modeling undermining defeaters in the view of default theories requires changing the set of premises upon receiving new information. To model changes to premises, we give a dynamic aspect to default justification logic by using the techniques from the logic of belief revision. More specifically, undermining is modeled with belief revision operations that include contracting a set of premises, that is, removing some information from it. The novel combination of default reasoning and belief revision in justification logic enriches both approaches to reasoning under uncertainty. By the end of the paper, we show some important aspects of defeasible argumentation in which our logic compares favorably to structured argumentation frameworks.

710 A Novel Ventriculoperitoneal Shunt Design Aiming to Reduce Shunt Failure Rates

Introduction Ventriculoperitoneal (VP) shunt insertion is the most common surgical treatment for hydrocephalus. While shunt obstructions are frequent and subsequent revision operations carry significant morbidity, there is limited advancement in shunt design to address this problem. Method A literature review of aetiology and mechanism of shunt blockage was performed. Design concepts of current medical and non-medical grade devices were studied. Design improvements to VP shunt were focused on the proximal catheter and lumen configuration. Concept dimensions and computer flow simulations using different diameters were generated. Results An improved prototype VP shunt design was proposed. It has multiple lumens and communicating channels between neighbouring lumens to provide alternative routes for cerebrospinal fluid drainage in the event of individual lumen obstruction. Our design also features a novel cone-shaped proximal end to minimise occlusion by nearby choroid plexus. Conclusions By targeting common causes of VP shunt blockage through proposed novel design, the mean service-life of shunts can be extended, necessitating fewer revision procedures and reducing both patient health and financial burdens. Further investigation, optimisation, and validation of this proposed shunt design is required before further product development.

ENDOPROSTHETIC REPLACEMENTIN PATIENTS WITH TUMORS OF BONES AND JOINTS: REVISION SURGERY

The article analyzes complications after individual oncological endoprosthesis replacement in tumor lesions of bones and joints, which led to repeated endoprosthesis replacement. After operations of endoprosthesis replacement of bones and joints with tumor lesions, the following complications were observed: periprosthetic infection — 7.4%, aseptic instability of the stem of endoprosthesis —13.1%, destruction of the endoprosthesis structure - 2.3%, wear of polyethylene inserts — 1.7%. Revision endoprosthesis replacement due to complications after endoprosthesis replacement of bones and joints for tumors was performed in 38 (21.7%) cases. Repeated endoprosthesis replacement of knee joint was performed in 22 cases, repeated endoprosthesis replacement of hip joint was performed in 6 cases, repeated endoprosthesis replacement of elbow joint was performed in 4 cases, repeated endoprosthesis replacement of shoulder joint was performed in 3 cases, repeated endoprosthesis replacement of tibial shaft was performed in 2 cases, repeated endoprosthesis replacement of ankle joint was performed in 1 case. The factors that led to complications and repeated endoprosthesis replacement were presented. In case of an infectious complication, it was recommended to install a metal-on-cement spacer, followed by repeated endoprosthesis replacement; in case of aseptic instability of the stem of endoprosthesis, repeated endoprosthesis replacement was performed with replacement of only one (loose) component of the endoprosthesis using a long intramedullary nail or replacement of the entire endoprosthesis; in case of the destruction of endoprosthesis structure, the repeated endoprosthesis replacement of the joint was effected with replacement of the entire endoprosthesis structure; when the polyethylene inserts were worn out, the repeated endoprosthesis replacement was performed with the replacement of the polyethylene inserts. After repeated endoprosthesis replacement, repeated revision operations were performed in 10 (26.3%) cases.

Longitudinal Epiphyseal Bracket as an Overlooked Etiology of Congenital-Residual Hallux Varus: A Case Report

Longitudinal epiphyseal bracket is a rare ossification disorder of the short tubular bones. The affected bone becomes deformed as a result of the bracket. The normal growth pattern cannot occur, and when it affects the first metatarsal bone, hallux varus may develop with the abnormal growth pattern. We present such a 6-year-old patient who had undergone surgery at 6 months of age for hallux varus and polydactyly. The deformity had worsened gradually after the initial operation because of the overlooked longitudinal epiphyseal bracket. The patient was treated with surgical excision of the epiphyseal bracket, with corrective medial open wedge osteotomy and split transfer of the extensor hallucis longus tendon. The result was excellent at the 20-month follow-up. At an early age, patients who present with hallux varus must be checked for the epiphyseal bracket, which can be invisible on radiographs because of the chondral structure. Untreated or overlooked patients with epiphyseal bracket will need revision operations for recurrent deformities.

Recurrent Subungual Viral Warts

Warts, cutaneous manifestations of human papillomavirus infection, are difficult to cure. Warts have a high recurrence rate and there is no known single completely effective treatment. In this case, a 14-year-old boy presented with a subungual wart of the thumb that did not respond to salicylic acid. Excision was performed due to discomfort caused by pain and deformation of the nail plate. After the first operation, the patient had to receive two revision operations due to recurrence. Epithelialization was completed 2 weeks after the second revision surgery, after which there was no recurrence. According to literature review, many immunocompetent patients can expect spontaneous recovery without any treatment. If treatment is necessary, salicylic acid and cryotherapy have the strongest evidence of efficacy and are recommended as first-line treatments. Various other treatments are used alone or in combination. During surgical removal, special attention should be given for complete removal of the wart to prevent recurrence.

Stenosis of the vertebral canal of the lumbar spine

The overall incidence of symptomatic lumbar spinal stenosis is about 1015% among persons aged 5070 years. Due to the aging of the population, the incidence of this pathology is constantly growing. The desire of older patients to preserve their quality of life and their functional abilities, along with the improvement of surgical techniques, leads to an increase in the number of surgical interventions for lumbar stenosis. This publication describes the classification of spinal canal stenosis. The clinical picture of this disease has been studied in detail. A special attention is paid to such diagnostic methods as computed tomography (CT), radiography, CT-myelography, magnetic resonance imaging (MRI). Various methods of surgical treatment decompression and decompression-stabilization are described in detail.. The efficiency of various types of decompression operations are 7280%, the results of surgery not differing statistically between the types of decompression (hemilaminectomy, interlaminectomy). Decompression-stabilization operations are used for progressive degenerative spinal deformity, destabilization after the surgical treatment, and disruption of the vertebral-pelvic relations. Currently, the following types of stabilization are used in the lumbar stenosis surgery: ALIF, PLIF, PLF, TLIF, XLIF, OLIF, and transpedicular fixation. The rate of complications in the stabilizing interventions is 27.6%; after decompression operations 9.7%. The frequency of revision operations is also higher after stabilization 10.3%, while after decompression it is 6.5%, which makes us cautious about these types of interventions. Systems of interosseous fixation are also used in the treatment of lumbar stenosis. In the 14 years of followup after interosseous fixation and decompression in 142 patients, 30 (21.1%) patients underwent revision interventions, with chronic pain (38.5%) and disc herniation (42.3%) being the main indication for repeated surgery in 26 of them.

Fixation Stability and Stiffness of Two Implant Systems for Proximal Femoral Varization Osteotomy

Proximal femoral varization osteotomy is a well-established surgical procedure in children with severe hip problems. This study aimed to evaluate the fixation stability and stiffness of two new implant systems. A biomechanical testing model was created with a total of 12 synthetic femora. Proximal femoral varization osteotomy was performed in every femur, and the synthetic femora were fixed with two different implant systems (PediLoc Locking Proximal Femur Plate System versus PediLoc Locking Cannulated Blade Plate System; OrthoPediatrics, Warsaw, IN, USA). The average torsional stiffness of the locking plate group was higher than for the cannulated blade plate group. Differences in internal and external rotations were seen between the two groups, but they were not significant. Using the tested implants in severe osteoporotic bones might show other results. Therefore, it might be helpful to use the locking plate system in osteoporotic bones and in cases of revision operations where stability is of critical focus.

What Characteristics of the Acetabular Defect Influence the Choice of the Acetabular Component During Revision Hip Arthroplasty?

The purposes of the retrospective cohort study were: 1) to determine the severity of defects in the acetabulum and the probable causes of their formation in patients who underwent revision hip arthroplasty (RHA), as well as an assessment of factors that exacerbate the severity of the defects; 2) identifying the proportion of severe defects in the overall structure of acetabular revisions and determining the effectiveness of using serial implants in comparison with individual constructions made by 3D printing; 3) the rationale for rational indications for the use of individual constructions.Materials and Methods. The structure and reasons for the formation of bone defects in the acetabulum were evaluated in 726 cases of revisions performed from 2004 to 2018. In addition, the results of revision operations in a group of patients with severe defects (type 3 according to Paprosky and pelvic discontinuity) were evaluated.Results. The most frequent cause of defect formation was iatrogenic (53.2%), and the share of severe defects was 39.5% (287 observations). A factor aggravating the severity of the defect is the lack of its limitation by the support bone. The results of RHA in patients with severe defects were assessed in 186 cases out of 287 (64.8%). In 73 (39.2%) cases, individual constructions were used, the average follow-up was 26 months. (from 12 to 50), and in 113 (60.8%) cases, serial implants were used, the average follow-up period was 62 months. (12 to 186). Individual constructions were more often implanted in patients with 3B acetabular defects (p<0.05) and its uncontained defects (p<0.001). The number of cases of aseptic loosening in the group of patients undergoing endoprosthetics using serial implants was greater than in the group of patients with individual constructions for the entire period (p<0.05) and in the early stages of observation (p<0.05).Conclusion. In case of RHA in patients with severe acetabular defects, individual implants, in comparison with serials, demonstrate better survival with an average follow-up of 26 months and due to design features, they can count on great long-term effectiveness. This study needs to be continued to increase follow-up.

Total hip replacement in femoral head osteonecrosis

The experience of hip replacement in young patients with osteonecrosis of the femoral head was analyzed in the article. The results of operations in the osteonecrosis group and osteoarthritis group in 3 years and 7 months after operations were compared. In 97.5 % of cases, cementless fixation implants with a ceramic on ceramic friction pair (45 %) and ceramic on polyethylene friction pair (45 %) were used. Surgical approaches by Moore, Hardinge and AMIS technique were applied. The clinical results of operations in the studied groups were similar, but the survival rate of endoprostheses in the osteonecrosis group was 91.5 %, and in the osteoarthritis group 97.2 %. In the osteonecrosis group an increased frequency of complications (dislocation of the endoprosthesis head, periprosthetic fracture, periprosthetic infection) and revision operations were observed. Our results show the influence of risk factors, concomitant diseases, the level of activity of young patients on the long-term total hip arthroplasty result.