The Impact of Temperature Conditions on the Manufacturing Process and Mechanical Behavior of Beverage Can Ends during Operation.

This article investigates the impact of temperature regimes, corresponding to various climatic zones, on the manufacturing process and operation of beverage can ends made of aluminum alloy AA5182. The production process of aluminum beverage can ends involves multiple steps, including melting, rolling, and stamping, where different temperatures can influence both the production process and the properties of the final product. Furthermore, the mechanical behavior of the final product is affected by the aging process of alloy AA5182, which progresses at varying rates depending on the temperature conditions during storage. The objective of this study is to simulate the production process under various climatic conditions using the finite element method (FEM) and experimentally investigate the dependence of the strength of alloy AA5182 can ends on storage time and temperature. The findings of the study reveal that, under temperature conditions corresponding to warmer climates, the punching force can be reduced by approximately 15% compared to production in colder climates. Additionally, the strength of the finished can exhibits a decrease of about 10% during a month of storage in a warm climate, while no significant decrease was observed in colder climates. These results hold practical significance for the beverage production industry, as the manufacturing and operation of beverage cans are localized in diverse climatic zones.

Pigmented Villonodular Synovitis - Various Manifestations, Inconsistent Terminology and Treatment. Cases Study.

Pigmented villonodular synovitis (PVNS) as well as tenosynovial giant cell tumor (TGCT) are both diagnosed and described in two forms, namely a localized and diffuse type. They form a diverse group of proliferative lesions in articular synovium and tendon sheaths. The inconsistent terminology impedes communication between patients, orthopedic surgeons, radiologists and pathologists, leading to misunderstandings and delaying treatment. In this paper, we present three cases of PVNS/TGCT (involving the fourth toe extensor tendon sheath, hip joint after resurfacing and flexor hallucis longus tendon sheath) together with suggestions regarding the unification of the terminology as well as diagnosis and treatment.

Peripheral snap-fit locking mechanisms and smooth surface finish of tibial trays reduce backside wear in fixed-bearing total knee arthroplasty.

Background and purpose - Severe backside wear, observed in older generations of total knee replacements (TKRs), led to redesign of locking mechanisms to reduce micromotions between tibial tray and inlay. Since little is known about whether this effectively reduces backside wear in modern designs, we examined backside damage in retrievals of various contemporary fixed-bearing TKRs. Patients and methods - A consecutive series of 102 inlays with a peripheral (Stryker Triathlon, Stryker Scorpio, DePuy PFC Sigma, Aesculap Search Evolution) or dovetail locking mechanism (Zimmer NexGen, Smith and Nephew Genesis II) was examined. Articular and backside surface damage was evaluated using the semiquantitative Hood scale. Inlays were examined using scanning electron microscopy (SEM) to determine backside wear mechanisms. Results - Mean Hood scores for articular (A) and backside (B) surfaces were similar in most implants-Triathlon (A: 46, B: 22), Genesis II (A: 55, B: 24), Scorpio (A: 57, B: 24), PFC (A: 52, B: 20); Search (A: 56, B: 24)-except the NexGen knee (A: 57, B: 60), which had statistically significantly higher backside wear scores. SEM studies showed backside damage caused by abrasion related to micromotion in designs with dovetail locking mechanisms, especially in the unpolished NexGen trays. In implants with peripheral liner locking mechanism, there were no signs of micromotion or abrasion. Instead, "tray transfer" of polyethylene and flattening of machining was observed. Interpretation - Although this retrieval study may not represent well-functioning TKRs, we found that a smooth surface finish and a peripheral locking mechanism reduce backside wear in vivo, but further studies are required to determine whether this actually leads to reduced osteolysis and lower failure rates.

Remodeling of bone tissue around the distal part of Zweymüller stem.

BACKGROUND: The Zweymüller stem is well-known in Europe and widely used for total hip replacement since 1980. Few authors have noted the presence of increased bone density below the tip of the stem; however, the underlying mechanism is still unknown. The aim of this study was to reveal factors influencing bone remodeling around the tip of the Zweymüller stem. MATERIAL AND METHODS: 102 consecutive patients (69 women and 33 men) who received a second generation Zweymüller type stem (123 prostheses) were included. Mean follow-up was 9.2 years (6 - 15 years). A Cortical Index (CI) was defined as the ratio between stem width and external cortical diameter in Gruen zones 3 and 5. RESULTS: Patients with a wide femoral canal and thin cortical bone (CI ≥0.4) demonstrated a positive correlation with the presence of increased bone density (IBD) below the stem (p<0.0001, r=0.6028). During follow-up, the mean Cortical Index decreased by 0.02 points and mean thickness of cortical bone in zone 3 and 5 increased by 2.0 millimeters. Cortical thickening was more pronounced in cases without IBD (1.5 vs. 2.4 mm, p=0.0172). CONCLUSIONS: 1. Thin cortical layers and a wide femoral canal (CI ≥0.4) can result in the presence of IBD below the stem. 2. IBDs probably appear due to mechanical stress transferred by the tip of stem to cancellous bone in Gruen zone 4. 3. Based on clinical symptoms, we conclude that the presence of IBD is not associated with increased aseptic loosening or stem instability.

Knee Function and Subjective Stability Following Total Condylar Arthroplasty in Joints with Preoperative Varus or Valgus Deformity.

BACKGROUND: Total knee arthroplasty in joints with valgus or varus deformity is technically demanding. Careful soft tissue balance as well as restitution of anatomical knee axis has a profound effect on postoperative function of the joint, however little is known about differences in subjective stability following surgery between preoperative valgus and varus knees. MATERIAL AND METHODS: Studied group consisted of 60 patients who underwent total condylar knee arthroplasty with one type of implant (Stryker Triathlon). Mean follow-up was 2,9 years (1-6 years). The group included 25 patients with valgus and 35 patients with varus preoperative deformity. All patients filled Knee Injury and Osteoarthritis Outcome Score (KOOS) forms. Detailed clinical and radiological assessment was performed. RESULTS: Mean KOOS score was slightly higher in patients with varus deformity, as compared to cases with valgus deformity. At physical examination higher LCL deficiency rate was observed in varus knees. Subjective instability was reported by eight patients (5 valgus and 3 varus). In all cases instability coexisted with decreased MCL tightness and implant position was correct in those patients. No subjective instability was reported by patients with clinical LCL deficiency. Furthermore KOOS scores in these patients were higher (85,8) as compared to cases with decreased MCL tension (79,1). CONCLUSIONS: 1. In patients with proper implant alignment subjective instability is related to postoperative MCL deficiency, regardless preoperative deformity in coronal plane. 2. The post-op LCL laxity does not compromise subjective stability, nor influence subjective outcome, as demonstrated with KOOS scores.

[Assessment of the level of metal ions in the blood of patients after hip resurfacing--preliminary report]. / Ocena poziomu jonów metali we krwi pacjentów po endoprotezoplastyce powierzchniowej--doniesienie wstepne.

INTRODUCTION: Metal-on-metal bearings characterize lower wear than metal-poly, lower fracture risk than ceramics and they allow for the manufacturing of large diameter heads. The metal ion release from the bearings is the the major concern of these articulations. MATERIAL: The study group consisted of 16 patients who underwent hip resurfacing with Durom implant and had minimum 1 year follow-up period. Blood from the patients was collected 4 times: before the surgery, 2, 6 and 12 months postoperatively. METHODS: Clinical examination was done according to HHS, Radiographic image was used to measure the cup inclination, evaluation of chromium and cobalt ion blood levels was performed using graphite furnace atomic absorbtion spectrometry (GFAAS). RESULTS: The levels of cobalt and chromium increased postoperatively significantly to decrease slightly at 6 months. At 1 year cobalt levels increased to the similar level like at at 2 months. The chromium level decresed to the values as low as preoperatively. The mean cup inclination angle measured on X-rays was 48 degrees(range 39 degrees - 56 degrees). The mean HHS result was 89.86 (range 64.43 to 98.73). The mean activity level measured with UCLA scale was 6 (range 3-9). CONCLUSIONS: The metal ion blond levels increase sigficantly in the period 2-6 months following hip replacement with large diameter metal-on-metal articulation. In further examinations at 1 year post-op ion levels decrease.

[Porous tantalum modular cups in revision hip arthroplasty]. / Zastosowanie modularnych komponentów z porowatego tantalu w endoprotezoplastyce rewizyjnej panewki stawu biodrowego.

INTRODUCTION: Modem indications for use of cemented or uncemented implants in revision hip arthroplasty are comparable. The use of bone cement provides predictable short term results, but the lack of osteointegration deteriorates its long term durability. Uncemented implants undergo osteointegration, but reduced contact with host bone may cause early loosening. Modular porous tantalum implants are highly osteointegrative, and the availability of bone stock augments increases the versatility of this system. MATERIAL AND METHODS: The study group consisted of 20 patients (21 hips) who underwent a revision hip arthroplasty using Trabecular Metal acetabular revision system. The follow-up period was between 7 and 31 months (average 20 months). All patients were evaluated with HHS and conventional radiography. RESULTS: The mean HHS increased form40.45 (range 18.74-56.65) preoperatively to 78.8 (56.5-96) at the last follow-up. No mechanical failures, nor septic complications were noted.

[Total knee replacement in joints with severe varus and bone deficiency]. / Endoprotezoplastyka stawu kolanowego ze znaczna szpotawoscia i deficytem kostnym.

INTRODUCTION: Total knee replacement in knees with severe valgus and defects of the medial tibial condyle are at higher risk complications than in knees with a correct axial allignement. MATERIAL AND METHODS: The study group included 10 patients (11 knees) with with severe valgus and defects of the medial tibial condyle in which TKR was performed. In 8 cases bone defects were filled with bone autograft in 3 cases defects were filled with metal augments. The mean follow-up was 37 months (26 months to 4 years). Clinical results were measured with the knee society score, the level of activity was evaluated with the UCLA score. Radiographic evaluation was based on radiograms taken preoperatively, postoperatively and at the follow-up examination. RESULTS: In All cases an improvement in clinical results was noted, the mean KSS result rised from 25.3 preoperatively to 87 postoperatively and the level of activity rised from 3.4 to 5.4 postoperatively. No signs of loosening were found in radiographic evaluation. CONCLUSIONS: TKR in joint with severe varus and medial tibial condyle defects creates a need for the reconstruction of defects. In lesser defects reconstruction with bone autografts is sufficient, in severe cases filling the defect with metal augments is needed. When indicitions are followed both methods provide good clinical results.

[Physical activity and quality of life following total uncemented hip replacement and hip resurfacing]. / Aktywnosc fizyczna i jakosc zycia po endoprotezoplastyce bezcementowej oraz kapoplastyce stawu biodrowego.

INTRODUCTION: The influence of physical activity on the survival of total hip replacement remains not fully recognized. It is unclear which activities are beneficient for patients following THR. MATERIAL: The study was conducted on group of 87 patients (94 hips) following uncemented THR with ABGII/Trident and 45 patients (51 hips) following hip resurfacing. The follow-up period was 6-30 months for THR group and 6-42 months for resurfacing group. METHODS: The patients answered a questionnaire based on WOMAC and SF-36 score, UCLA activity scale with additional questions concerning patients physical activity, working and place of living. RESULTS: In WOMAC, physical domains of SF-36 and UCLA activity score patients following hip resurfacing showed better results. The most preferred activity in both groups was exercise walking and biking. The last one was particularly preferred by patients living in rural areas. CONCLUSION: The vast majority of patients restricted their activity to disciplines with a safe range of hip weight bearing.

[Evaluation of outcomes following total hip arthroplasty]. / Ocena odleglych wyników endoprotezoplastyki stawu biodrowego proteza bezcementowa typu Zweymüller.

BACKGROUND: Osteoarthritis of the hip, one of the most frequent civilization diseases, causes not only a large physical and psychological stress for the patients but also generates increasing costs of treatment each year. The aim of our study was to evaluate the patients' functioning in the period of 3-12 years after the Zweymüller total hip arthroplasty. MATERIAL AND METHODS: 323 patients, aged 27-83 years, after the primary Zweymüller cementless total hip arthroplasty, operated in the Orthopedics and Traumatology Department of Poznan University of Medical Sciences. The evaluation was based on the Western Ontario and McMaster Universities (WOMAC) questionnaire supported with additional questions concerning the weight, height, dwelling place, education level, occupational activity, additional diseases and other joints problems. RESULTS: The Zweymüller cementless total hip arthroplasty is characterized by a good stability in 97.8% of patients during the 3-12 years of postoperational period. Additional problems associated with any unoperated lower limb joint almost always result in the increase of the WOMAC score. A positive correlation was also noticed between the level of education and the occupational activity after the treatment in patients with similar WOMAC score. No influence of overweight on the postoperative activity occured. Moreover our study revealed a negative correlation between BMI (Body Mass Index--range up to 40) and the WOMAC form. CONCLUSIONS: The functional evaluation of patients after total hip arthroplasty should consider information about other lower limbs joints problems for better objectivity. It should be mentioned that the occupational activity correlates positively with the level of patients education. The obesity cannot be the criteria disqualifying from the operation as it does not influence the activity after the hip replacement.

[Quality of life in patients before and after total hip arthroplasty]. / Jakosc zycia u chorych przed i po endoprotezoplastyce stawu biodrowego.

INTRODUCTION: Osteoarthritis is the most common joint disease in adults and according to WHO is one of the civilisation threats. Total joint replacement is the best method of treatment of severe osteoarthritis. MATERIAL AND METHODS: The study group consisted of 62 (44 women, 18 men) patients, who due to the severe osteoarthritis underwent total hip replacement at the Department of Orthopaedics Poznan University of Medicine. The mean age was 63 (range 30-87). For the evaluation of the quality of life the modified questionnaire WHOQOL-100 was used. The first evaluation was performed before the surgery, the second one 12-18 (average 14) months postoperatively. RESULTS: At the final evaluation the improvement was observed in the following domains: physical, psychological, level of independence, environmental and the global quality of life. No change was observed in the domain "social relations". The greatest improvement was observed in the following subscales: "pain and discomfort", "vitality and fatigue", mobility, "everyday activities", "drug dependence", transportation. No significant change was found in the following subscales: "sleep and rest", "positive feelings", "ability to work and learn", "personal social relations" and accessibility and quality of healthcare.