Simultaneous bilateral total hip arthroplasty (THA) in patients with bilateral hip osteoarthritis is gradually becoming attractive, as it requires a single anesthesia and hospitalization. However, there are concerns about the potential complications following this surgical option. The purpose of this study is to compare the short-term major and minor complications and assess the readmission rate, between patients treated with same-day bilateral THA and those with staged procedures within a year.

We retrospectively reviewed the charts of all patients with bilateral hip osteoarthritis that underwent simultaneous or staged (within a year) bilateral total THA in our institution, between 2016-2020. Preoperative patient variables between the two groups were compared using the 2-sample t-test for continuous variables, the Fisher's exact test for binary variables, or the chi-square test for multiple categorical variables. Similarly, differences in the 30-day major and minor complications and readmission rates were assessed. A logistic regression model was also developed to identify potential risk factors.

A total of 160 patients (mean age: 64.3 years, SD: ±11.7) that underwent bilateral THA was identified. Seventy-nine patients were treated with simultaneous and eighty-one patients with staged procedures. There were no differences in terms of preoperative laboratory values, gender, age, Body Mass Index (BMI), or American Society of Anesthesiologists Scores (ASA) (p>0.05) between the two groups. Patients in the simultaneous group were more likely to receive general anesthesia (43% vs 9.9%, p0.05). After controlling for potential confounders, the multivariable logistic regression analysis showed similar odds of having a major (odds ratio 0.29, 95% confidence interval [0.30-2.88], p=0.29) or minor (odds ratio 1.714, 95% confidence interval [0.66-4.46], p=0.27) complication after simultaneous compared to staged bilateral THA. No differences in emergency department visits or readmission for reasons related to the procedure were recorded (p>0.05).

This study shows that similar complication and readmission rates are expected after simultaneous and staged THAs. Simultaneous bilateral THA is a safe and effective procedure, that should be sought actively and counselled by surgeons, for patients that present with radiologic and clinical bilateral hip disease.

Osteoarthritis (OA) is one of the most common causes of knee pain in the aging population and presents with higher odds with increased BMI. Total knee arthroplasty (TKA) has become the standard of care for the treatment of OA. Over “719,000 TKA's were performed in 2010 in the USA alone, with dramatic economic burden- costing 16,000 USD per TKA” (CDC 2012). Over the past two decades, this cost was compounded by the unknown increasing rate of primary TKA and cannot be explained by the expanding population or worldwide obesity epidemic. These facts raise two key questions: are patients' quality of life expectations higher and driving the TKA rate up, or have surgeons changed their indications and started to operate on less disabled people? Our study aimed to determine the average functional profile for patients undergoing TKA using patient reported Outcome Measure (SF-36), to document if preoperative SF-36 scores have changed over the past two decades, and lastly to asses if patient pre-operative SF-36 scores are lower in in the USA vs the rest of the world.

A literature search of Medline, Embase and Cochrane databases was performed extracting data from publishing year 1966 to 2016 with a search date of Dec 12, 2016. Two independent reviewers revised the abstracts and excluded articles with: no TKA, revision TKA, no pre-op SF-36, no SF-36 reported, incomplete scores to calculate SF-36, duplicates, review article, meta-analysis, letter to the editor, conference proceeding or abstract, disagreements were resolved with a third reviewer. All languages were included to maximize the catchment of data. All remaining articles were independently read and excluded if they did not provide data required for our study. Included articles were analyzed for data including: for year of patient enrollment, location (USA vs. non-USA), pre-operative SF-36 mental (MCS) and physical (PCS) component summary, level of evidence. Recorded data was compared post completion to assess inter-observer accuracy as per PRISMA guidelines for meta-analysis.

After applying all the exclusion criteria on 923 selected abstracts, a total of 136 articles of which 30 were randomized control trials, were completely reviewed and included in our study. A total of 56,713 patients' physical component scores were analyzed and revealed an overall pre-operative SF-36 physical component score 31.93. When stratifying the data, it was revealed that patients operated in the USA had an average score of 32.3 whereas Non-US countries were 31.7, with no statistical significance. No statistical difference between SF36 scores was seen over time amongst studies of all nations.

Based on the results of this study, we have shown that orthopaedic surgeons are performing TKA universally at the same pre-operative scores, independent of country of origin or year of surgery. The indications thus have remained consistent for two decades regardless of the advances in technology. Functional profiles of patients appear similar among US and Non-US countries. Further, we infer that based on pre-operative SF-36 PCS scores, the optimal time to undergo a TKA is when PCS is 31.9 +/−3.

Osteoarthritis (OA) is a multifactorial debilitating disease that affects over four million Canadians. Although the mechanism(s) of OA onset is unclear, the biological outcome is cartilage degradation. Cartilage degradation is typified by the progressive loss of extracellular matrix components - aggrecan and type II collagen (Col II) – partly due to the up-regulation of catabolic enzymes - aggrecanases a disintegrin and metalloprotease with thrombospondin motifs (ADAMTS-) 4 and 5 and matrix metalloproteinases (MMPs). There is currently no treatment that will prevent or repair joint damage, and current medications are aimed mostly at pain management. When pain becomes unmanageable arthroplastic surgery is often performed. Interest has developed over the presence of calcium crystals in the synovial fluid of OA patients, as they have been shown to activate synovial fibroblasts inducing the expression of catabolic agents. We recently discovered elevated levels of free calcium in the synovial fluid of OA patients and raised the question on its role in cartilage degeneration.

Articular cartilage was isolated from 5 donors undergoing total hip replacement. Chondrocytes were recovered from the cartilage of each femoral head or knee by sequential digestion with Pronase followed by Collagenase and expanded in DMEM supplemented with 10% heat-inactivated FBS. OA and normal human articular chondrocytes (PromoCell, Heidelberg, Germany) were transferred to 6-well plates in culture medium containing various concentrations of calcium (0.5, 1, 2.5, and 5 mM CaCl2), and IL-1β. Cartilage explants were prepared from the same donors and included cartilage with the cortical bone approximately 1 cm2 in dimension. Bovine articular cartilage explants (10 months) were used as a control. Explants were cultured in the above mentioned media, however, the incubation period was extended to 21 days. Immunohistochemistry was performed on cartilage explants to measure expression of Col X, MMP-13, and alkaline phosphatase. The sulfated glycosaminoglycan (GAG, predominantly aggrecan) content of cartilage was analyzed using the 1,9-dimethylmethylene blue (DMMB) dye-binding assay, and aggregan fragmentation was determined by Western blotting using antibody targeted to its G1 domain. Western blotting was also performed on cell lysate from both OA and normal chondrocytes to measure aggrecan, Col II, MMP-3 and −13, ADAMTS-4 and −5.

Ca2+ significantly decreased the proteoglycan content of the cartilage explants as determined by the DMMB assay. The presence of aggrecan and Col II also decreased as a function of calcium, in both the human OA and bovine cartilage explants. When normal and OA chondrocytes were cultured in medium supplemented with increasing concentrations of calcium (0.5–5 mM Ca2+), aggrecan and Col II expression decreased dose-dependently. Surprisingly, increasing Ca2+ did not induce the release of MMP-3, and −13, or ADAMTS-4 and-5 in conditioned media from OA and normal chondrocytes. Interestingly, inhibition of the extracellular calcium-sensing receptor CaSR) reversed the effects of calcium on matrix protein synthesis.

We provide evidence that Ca2+ may play a direct role in cartilage degradation by regulating the expression of aggrecan and Col II through activation of CaSR.

Purpose

Metal-on-metal (MoM) articulations in total hip replacement (THR) have become an attractive option for young, active patients. Short-term reports have demonstrated elevated systemic metal ion levels in the blood and urine. Disseminated concentrations of cobalt and chromium have raised concern regarding cellular toxicity, chromosomal damage and adverse local soft tissue reactions.

Long-term studies are required to support the increased use of MoM bearings in younger patients given their potential deleterious effects. The purpose of the current study was to report the seven to 13 year clinical, radiographic, and metal ion results in patients following MoM THR.

Purpose

The purpose of the study was to determine the rate of conversion from RSA to THR in a number of Canadian centers performing resurfacings

Purpose: Several studies have shown elevated levels of metal ions in blood of patients with metal-on-metal (MM) total hip arthroplasty (THA). The outstanding question that remains is the clinical impact of these elevated ion levels. Even though it is well known that exposure to heavy metals such as lead, copper, mercury, nickel, and cadmium) may lead to significant alterations in human sperm morphology and motility, less is known on the effect of Co and Cr on semen parameters. The aim of the present study was to investigate the effect of metal ions on the semen of males of child fathering age with MM hip arthroplasty.

Method: Semen was collected form 10 patients between 41 and 49 years old (mean = 45±6 years) by masturbation after 2–3 days of abstinence. Samples were examined within 1h after ejaculation for morphology, motility, and number of sperm cells following standard criteria from the World Health Organization (WHO). Co and Cr concentrations were measured in both the seminal plasma and in the blood of patients by inductively coupled plasma-mass spectroscopy (ICP-MS). Since spermatozoa membrane polyunsaturated fatty acids are vulnerable to attack by reactive oxygen species (leading to peroxide formation), peroxide concentrations were measured in both the seminal plasma and the blood of patients.

Results: Results showed that the concentration of both Co and Cr ions was significantly lower in the seminal plasma than in the blood of the patients. Results also showed that the levels of peroxides were lower in the seminal plasma than in the blood plasma of these patients. Importantly, the ejaculate volume, the sperm density, the total sperm count, the pH, and the percentage of cells with normal morphology were in the range of the WHO criteria for fertile population and also in the range of reference patients in the city of measurements. However, the viability was a little bit lower than what was observed in a fertile population without prosthesis.

Conclusion: The presence of Co and Cr ions in the blood of males of child fathering age with MM hip arthroplasty raised concerns about the quality of semen in these patients. Results of the present study strongly suggest that the raised of Co and Cr had no significant effect on sperm parameters of young patients with MM prosthesis. The methods used to identify potential normal and fertile semen samples are still contradictory and not exactly defined. Studies showed for example that only total numbers of sperm with progressive mobility are significantly different in the fertile than in sub-fertile men, while others suggested that the fertile population should be defined by sperm concentration or sperm morphology. In conclusion, results suggest that Co and Cr ions generated from MM prosthesis have no significant effect on the sperm parameters of young patients of child fathering age. Further longitudinal studies are however necessary to conclusively determine the effect of metal ions from MM prosthesis on sperm parameters.

Purpose: Several studies have shown elevated levels of metal ions in blood of patients with metal-on-metal (MM) total hip arthroplasty (THA). To minimize wear, the elastohydrodynamic theory suggests wear reduction for larger diameter head bearings. This significant reduction in wear has been demonstrated in hip simulators for the 36 mm-head compared to the 28 mm-head prosthesis. However, the survival of larger head MM THAs and the levels of metal ions in the blood of patients having these implants are still to be determined.

Method: Fifty (50) patients (56 hips) who received a DePuy Ultamet™ MM hip bearing (40/44 mm-head) at our Institution between July 1st 2007 and August 31st 2008 were included in the study. Clinical and radiologic data were collected pre-operatively as well as at 6–8 weeks, 4–6 months, and 1 year postoperatively. Results were compared to those of subjects (65 patients, 71 hips) who received a 36 mm-head prosthesis. Cobalt (Co) and chromium (Cr) concentrations were measured at 1 year post-operatively in the blood of patients by ICP-MS. Since Co and Cr ions have the potential to induce irreversible biochemical damage to macromolecules, the levels of oxidative stress markers (total antioxidants and lipid peroxides) were measured in the plasma of these patients.

Results: At their 1-year post-operatively follow-ups, all patients were doing well and no sign of osteolysis was observed on X-rays. Harris Hip Score increased in both groups with a tendency to higher score in the 40–44 mm group compared to the 36 mm group. Activity score also increased in both groups after 1 year without statistical significant differences. Results also show that the levels of Co and Cr ions increased significantly in both groups compared to the Pre-OP control group. The levels of Co were also significantly higher in patients with large head arthroplasty (40 and 44 mm-head) compared to those of the 36 mm-head group (p=0.012). The levels of Cr were similar in both the large head and the 36 mm-head group (p=0.41). Finally, results show that there were no differences in the levels of total antioxidants and peroxides between the 40–44 mm group and the 36 mm group. Moreover, there was no increase in the level of these markers of oxidative stress compared to the Pre-OP control group.

Conclusion: The present study shows that at 1-year postoperatively, patients with large 40–44 mm-head THA had comparable clinical outcomes than those with 36 mm-head prosthesis. However, the levels of Co ions were significantly higher in these patients compared to patients with 36 mm-head THA. This suggests a higher health risk for these patients due to the presence of these ions. However, there were no effects on the levels of oxidative stress markers in the blood of these patients, suggesting that there is no increased risk at short-term. In conclusion, due to the high level of Co ions, longer follow-ups are required to conclusively determine the outcomes of the patients and the survivorship of these new bearings.

Purpose: The presence of metal ions in the blood of patients with a metal-on-metal (MM) bearing points to the importance of understanding the long-term effects of these ions. Metal ions have the potential to induce the production of reactive oxygen species (ROS), making them prime suspects for inducing molecular damage in circulating cells. The aim of this study was to analyze the levels of oxidative stress markers in the plasma of patients with hip surface replacement.

Method: Blood was collected up to 3 years after implantation from 66 patients with articular surface replacement (ASRÔ, DePuy Orthopaedics) and 54 patients with 36 mm-head MM THA. Forty (40) pre-operative patients were also assessed as control group. Total anti-oxidant levels were measured by the Oxford Biomedical total antioxidant power assay (Oxford, MI) to obtain an overview of the defense capacity of patient’s oxidative stress. Peroxide concentrations were measured by the Biomedica OxyStat assay (Medicorp, Montreal, QC) to quantify damage to lipids in the systemic circulation. Nitrototyrosine levels were quantified using the BIOXYTECH® Nitrotyrosine-EIA assay (OxisResearch™, Portland OR) to measure damage to proteins. The concentrations of metal ions were analyzed by inductively coupled plasma-mass spectroscopy.

Results: Results showed that there were no statistical differences in the concentrations of total antioxidants, lipid peroxides, and protein nitrotyrosines between the control, the ASR, and the 36 mm-head groups. Furthermore, there was no correlation between the concentrations of these markers and the concentrations of both Co and Cr ions (r2 £ 0.006).

Conclusion: The single most significant obstacle preventing a broader application of metal-on-metal hip arthroplasties and resurfacings continues to be the concerns regarding elevated metal ion levels in the blood and urine of patients. The present results showed that there were no changes in the levels of oxidative stress markers in patients with MM bearings compared to the control group. Given the possible latency periods related to metal ion exposure, longer follow-ups are required to conclusively determine the effects of elevated circulating ions on oxidative stress in the blood of patients with MM bearings.

Purpose: Metal-on-metal articulations in total hip arthroplasty (THA) have been recently re-introduced for the treatment of osteoarthritis. There have been excellent short-term clinical outcomes reported. The long-term clinical results of these implants are still unknown. In this study, we examined the four to ten -year results of metal-on-metal total hip arthroplasty at our institution.

Method: All patients receiving a metal-on-metal prosthesis were prospectively registered in a computerized database. The period July 1997 – May 2003 was selected for analysis. This group contained 251 cases (207 patients) and had an average follow-up of 6.8 years. Of the 251 implants the femoral head components were either Metasul^™ (203) or Ultamet^™ (48) and the acetubular component Fitek^™ (12), Interop^™ (191) or Pinnacle^™ (48). All patients were assessed with the Harris hip and UCLA activity scores at routinely scheduled follow-up visits. The mean age of patients at surgery was 52 years (18 to 70 years old). The average follow-up was of 6.8 years (4.2–10 years). No patients were lost to follow-up.

Results: The mean UCLA and Harris hip score pre-operatively were 3.6 (1–8) and 42 (15–81), respectively. Values of the UCLA and the Harris hip scores on the most recent follow-up visit were 7.0 (60% of patients had a score equal to or greater than 7) and 85 (70% of patients had a score equal to or greater than 85), respectively. Thirteen hips (5.1%) were revised in total: 1 (0.4%) for early deep infection, 1 (0.4%) for revision of undersized stem and 11 (4.3%) for acetabular revisions due to manufacturing defects. Radiological results showed no osteolysis and 9 non-progressive radiolucency.

Conclusion: At four to ten year follow-up, metal-on-metal total hip replacement provides consistently good clinical and radiographic results with a low revision rate. They provide longstanding pain alleviation and improved function and activity levels in patients suffering from osteoarthritis.

Purpose: Several studies have shown elevated levels of metal ions in the blood of patients with metal-on-metal (MM) total hip arthroplasty (THA). Even though there is no conclusive evidence that the elevated levels of ions have any detrimental effects on the patients, the presence of these ions is still a cause of concerns. The potential of metal ions released from MM implants for oxidative stress is unknown. In the present study, we measured the concentrations of oxidative stress markers in the plasma of patients with MM THAs.

Method: Blood from patients having MM THAs was collected up to 10 years post-operatively into Sarstedt Li-Heparin tubes. Plasma was prepared by centrifugation at 500 × g for 10 min. Plasma was chosen as opposed to whole blood because it is known that the assays for oxidative stress are not recommended for blood and can lead to erroneous data. Total antioxidant levels were measured by the Oxford Biomedical total antioxidant power assay to obtain an overview of the defense capacity of patients against oxidative stress. The activity of catalase and glutathione peroxidase, two antioxidant enzymes acting on specific reactive oxygen species, was measured by enzymatic assays. Peroxide concentrations were measured by the Biomedica Oxy-Stat assay to quantify damage to lipids in the systemic circulation. Nitrototyrosine levels were quantified using the BIOXYTECH® Nitrotyrosine-EIA assay to measure damage to proteins. Levels in patients without prostheses were used as control.

Results: There were no statistical differences in the concentrations of total antioxidants, lipid peroxides, and nitrotyrosines throughout the period of study. The activity of catalase and glutathione peroxidase was also stable over time. Moreover, there was no correlation between the concentrations of these markers and the concentrations of both cobalt and chromium ions.

Conclusion: Metal ions have the potential to induce the production of reactive oxygen species (free radicals) and cause oxidative stress in the plasma of patients with MM THAs. The present study showed that there were no changes in the levels of oxidative stress markers or antioxidant enzymes in these patients up to 10 years post-operatively. Taken together, the data strongly suggest that metal ions may not cause a significant oxidative stress in patients with MM THAs.

Although the response of macrophages to polyethylene debris has been widely studied, it has never been compared with the cellular response to ceramic debris. Our aim was to investigate the cytotoxicity of ceramic particles (Al₂O₃ and ZrO₂) and to analyse their ability to stimulate the release of inflammatory mediators compared with that of high-density polyethylene particles (HDP). We analysed the effects of particle size, concentration and composition using an in vitro model. The J774 mouse macrophage cell line was exposed to commercial particles in the phagocytosable range (up to 4.5 μm). Al₂O₃ was compared with ZrO₂ at 0.6 μm and with HDP at 4.5 μm. Cytotoxicity tests were performed using flow cytometry and macrophage cytokine release was measured by ELISA.

Cell mortality increased with the size and concentration of Al₂O₃ particles. When comparing Al₂O₃ and ZrO₂ at 0.6 μm, we did not detect any significant difference at the concentrations analysed (up to 2500 particles per macrophage), and mortality remained very low (less than 10%). Release of TNF-α also increased with the size and concentration of Al₂O₃ particles, reaching 195% of control (165 pg/ml v 84 pg/ml) at 2.4 μm and 350 particles per cell (p < 0.05). Release of TNF-α was higher with HDP than with Al₂O₃ particles at 4.5 μm. However, we did not detect any significant difference in the release of TNF-α between Al₂O₃ and ZrO₂ at 0.6 μm (p > 0.05). We saw no evidence of release of interleukin-1α or interleukin-1ß after exposure to ceramic or HDP particles.