Projected numbers of knee and hip arthroplasties up to the year 2030 in Japan

Evaluation of bone integrity around the acetabular cup using noninvasive laser resonance frequency analysis

Resonance frequency analysis (RFA) is valuable for assessing implant status. In a previous investigation, acetabular cup fixation was assessed using laser RFA and the pull-down force was predicted in an in vitro setting. While the pull-down force alone is sufficient for initial fixation evaluation, it is desirable to evaluate the bone strength of the foundation for subsequent fixation. Diminished bone quality causes micromotion, migration, and protracted osseointegration, consequently elevating susceptibility to periprosthetic fractures and failure of ingrained trabecular bone. Limited research exists on the evaluation of bone mineral density (BMD) around the cup using RFA. For in vivo application of laser RFA, we implemented the sweep pulse excitation method and engineered an innovative laser RFA device having low laser energy and small dimensions. We focused on a specific frequency range (2500-4500 Hz), where the peak frequency was presumed to be influenced by foundational density. Quantitative computed tomography with a phantom was employed to assess periprosthetic BMD. Correlation between the resonance frequency within the designated range and the density around the cup was evaluated both in the laboratory and in vivo using the novel laser RFA device. The Kruskal-Wallis test showed robust correlations in both experiments (laboratory study: R = 0.728, p < 0.001; in vivo study: R = 0.619, p < 0.001). Our laser RFA system can assess the quality of bone surrounding the cup. Laser RFA holds promise in predicting the risk of loosening and might aid in the decision-making process for additional fixation through screw insertion.

Knee arthroplasty: an international systemic review of epidemiological trends

BACKGROUND

In response to various socio-economic factors and technological advancements, knee arthroplasty procedures have steadily increased. To date, epidemiological analyses have been conducted on a single-country basis. The aims of this article are: (1) to identify arthroplasty databases by country, (2) to verify the international comparability of coding, (3) to study retrospective epidemiological trends, and (4) to analyze projections by country. The hypothesis is that countries will follow similar trends, though with varying time lags.

MATERIALS AND METHODS

A literature review from 2005 to 2023 was conducted following PRISMA recommendations on PubMed, Web of Science, and Cochrane, using the keywords: "Knee + Arthroplasty + Trends + Replacement + Epidemiology." Only articles featuring national analyses, based on references recognized by healthcare systems, were included.

RESULTS

Forty-eight articles, representing 16 countries, were selected. Europe was the most represented (47% of occurrences), followed by the USA (22%), Asia (20%), Oceania (8%), and Chile (2%). The data came from national databases or representative extrapolated samples. Extraction methods used precise national codes or specific definitions. Growth rates in volume and incidence were positive but varied between countries, with distinct dynamics and different phases of growth. Females had higher volumes and incidence rates (sex ratio 2/3), but growth was faster in males. Future forecasts, based on regression models (Poisson, linear, or logistic), predicted an increase in volumes of between +30% by 2030 and +805% by 2050.

CONCLUSION

The analysis of census systems revealed growth in knee arthroplasties in all countries, but with varying intensities depending on the period. These multifactorial disparities appeared to follow a similar pattern, staggered over time based on the countries' economic development.

LEVEL OF EVIDENCE

IV; epidemiological review.

A Bone Health Optimization Framework for Malaysia: a position paper by the Malaysian Bone Health Optimization Network (MyBONe)

This position paper aims to establish and standardise Bone Health Optimization (BHO) strategies for older patients undergoing elective orthopaedic surgeries in Malaysia. It emphasises pre-, intra-, and post-operative assessments and tailored management. Adopting the "5IQ" approach, it proposes clinical standards and a registry to improve surgical outcomes and patient care.

PURPOSE

Osteoporosis and osteopenia are highly prevalent among older patients scheduled for elective arthroplasties and spinal surgeries. This position paper aims to establish, promote, and standardise effective Bone Health Optimization (BHO) strategies for such patients within orthopaedic practices in Malaysia. It emphasises the need for bone health assessments to be undertaken at the pre-operative, intra-operative, and post-operative stages, with tailored management strategies to meet individual patient needs.

METHODOLOGY

A comprehensive literature review was conducted, focusing on articles published from 2019 to 2024. Twelve broad themes were defined including definitions and importance of BHO, epidemiological data, assessment techniques, risk stratification, management strategies, and outcome metrics.

RESULTS

Elective surgeries on patients with poor bone health are associated with adverse outcomes, such as periprosthetic fractures, aseptic loosening of implants, and complications after spinal surgeries. This position paper advocates for routine bone health assessments and monitoring during the pre-operative, intra-operative, and post-operative phases. It provides summaries of imaging modalities, risk assessment tools, and techniques for each phase. By adapting the successful "5IQ" approach from secondary fracture prevention, we propose 5IQ-based Clinical Standards for BHO, including 18 Key Performance Indicators. A Malaysian BHO Registry is proposed to benchmark care in real-time and support a national quality improvement programme. Practical resources, such as a BHO algorithm and key practice points, are included.

CONCLUSION

This position paper proposes a paradigm shift in the management of bone health for patients undergoing elective orthopaedic surgery in Malaysia, aiming to improve surgical outcomes and patient care through standardised BHO strategies.

Clinical outcomes and radiolucent line analysis in cementless mobile-bearing total knee arthroplasty: a prospective multicentre study in Japan

The objective of this study was to assess radiolucent lines (RLLs) and to determine their effect on clinical outcomes of the newly introduced cementless mobile-bearing total knee arthroplasty (TKA) system. This was prospective, multicentre study. Seventy-eight patients with knee osteoarthritis who underwent primary TKA were enrolled. Patient-reported outcome measures (PROMs) and radiographic assessments were evaluated at preoperative baseline and at 6 weeks, 1 year, and 2 years after surgery. KOOS, PKIP, 2011KSS, EQ-5D-3L and SKO improved from preoperative baseline to all postoperative timepoints, with no loosening of components. No RLLs were detected at 6 weeks after surgery. However, RLLs ≥ 1 mm developed in 2.8% of the patients for the femur and 9.7% for the tibia at 1 year after surgery, and values were 5.7% and 10.9%, respectively, at 2 years after surgery. RLL incidence was not correlated with PROMs. Age, sex, body mass index, range of motion knee flexion, posterior cruciate ligament treatment and β angle did not impact the occurrence of RLLs. There were no intraoperative complications, revisions or reoperations. This TKA system improved PROMs and showed less incidence of RLLs compared to the previous reported TKA without implant-related complications.

Insight into antibacterial effect of titanium nanotubular surfaces with focus on Staphylococcus aureus and Pseudomonas aeruginosa

Materials used for orthopedic implants should not only have physical properties close to those of bones, durability and biocompatibility, but should also exhibit a sufficient degree of antibacterial functionality. Due to its excellent properties, titanium is still a widely used material for production of orthopedic implants, but the unmodified material exhibits poor antibacterial activity. In this work, the physicochemical characteristics, such as chemical composition, crystallinity, wettability, roughness, and release of Ti ions of the titanium surface modified with nanotubular layers were analyzed and its antibacterial activity against two biofilm-forming bacterial strains responsible for prosthetic joint infection (Staphylococcus aureus and Pseudomonas aeruginosa) was investigated. Electrochemical anodization (anodic oxidation) was used to prepare two types of nanotubular arrays with nanotubes differing in dimensions (with diameters of 73 and 118 nm and lengths of 572 and 343 nm, respectively). These two surface types showed similar chemistry, crystallinity, and surface energy. The surface with smaller nanotube diameter (TNT-73) but larger values of roughness parameters was more effective against S. aureus. For P. aeruginosa the sample with a larger nanotube diameter (TNT-118) had better antibacterial effect with proven cell lysis. Antibacterial properties of titanium nanotubular surfaces with potential in implantology, which in our previous work demonstrated a positive effect on the behavior of human gingival fibroblasts, were investigated in terms of surface parameters. The interplay between nanotube diameter and roughness appeared critical for the bacterial fate on nanotubular surfaces. The relationship of nanotube diameter, values of roughness parameters, and other surface properties to bacterial behavior is discussed in detail. The study is believed to shed more light on how nanotubular surface parameters and their interplay affect antibacterial activity.

The Investigation of Preoperative Factors Associated With Postoperative Outcomes Following Total Knee Arthroplasty for Osteoarthritis: A Scoping Review

This study aimed to investigate preoperative factors associated with non-home discharges from acute care hospitals in patients undergoing total knee arthroplasty (TKA) due to osteoarthritis. It was a scoping review focused on patients who received their first unilateral TKA for osteoarthritis. The research targeted observational studies that examined the destinations of patients post-surgery based on preoperative factors, with a literature search conducted in April 2023. Out of 3,255 identified papers, 28 met the eligibility criteria. A total of 26 preoperative factors were identified as potentially related to discharge destinations, including age, gender, comorbidities, and obesity. By selecting an appropriate discharge destination based on preoperative factors, there may be potential for more efficient use of medical resources. Future studies should consider preoperative factors in the context of national healthcare systems and lengths of hospital stay.

Highly Porous Titanium Cups Frequently Presenting with Radiolucent Lines in Cementless Primary Total Hip Arthroplasty: A Retrospective Cohort Study

Background/Objectives: A highly porous titanium cup with a three-dimensional metal interface was recently introduced to improve biological fixation and survival. However, radiography has revealed concerns regarding these cups, despite their excellent short- and mid-term clinical outcomes. This study compared the clinical and radiographic results of a highly porous titanium cup with those of a hydroxyapatite-coated porous titanium cup after primary total hip arthroplasty (THA). Methods: Fifty-one primary THAs were investigated. A highly porous titanium cup was used in 17 hips, and a hydroxyapatite-coated porous titanium cup was used in 34 hips. No significant differences in preoperative patient demographic characteristics were observed between the two groups. The 2-year postoperative clinical and radiographic results were compared. Results: Radiolucent lines were observed in 13 (76%) of 17 hips with highly porous titanium cups and in none (0%) of 34 hips with hydroxyapatite-coated porous titanium cups (p < 0.001). In the highly porous titanium cup group, radiolucent lines were observed in five hips (29%) in one zone, two hips (11%) in two zones, and six hips (35%) in three zones. No cup loosening was observed in either group. Conclusions: Radiolucent lines were significantly more frequent in highly porous titanium cups. This study suggests that, compared to the three-dimensional structure of porous titanium, the hydroxyapatite coating of porous titanium had a greater influence on bone ingrowth in the short term. The meaning of these findings in the long-term is unclear yet.

Total knee arthroplasty: does ultra-early physical therapy improve functional outcomes and reduce length of stay? A retrospective cohort study

BACKGROUND

The Enhanced Recovery After Surgery (ERAS) Society recommends that after total knee arthroplasty (TKA), patients should be mobilized early. However, there is no consensus on how early physical therapy should be commenced. We aim to investigate whether ultra-early physical therapy (< 12 h postoperatively) leads to better outcomes.

METHODS

This is a retrospective cohort study of 569 patients who underwent primary TKA from August 2017 to December 2019 at our institution. We compared patients who had undergone physical therapy either within 24 h or 24-48 h after TKA. Further subgroup analysis was performed on the < 24 h group, comparing those who had undergone PT within 12 h and within 12-24 h. The outcomes analyzed include the Oxford Knee Scoring System score, Knee Society Scores, range of motion (ROM), length of stay (LOS) and ambulatory distance on discharge. A student's t test, chi-squared test or Fisher's exact test was used where appropriate, to determine statistical significance of our findings.

RESULTS

LOS in the < 24 h group was shorter compared to the 24-48 h group (4.87 vs. 5.34 days, p = 0.002). Subgroup analysis showed that LOS was shorter in the ultra-early PT (< 12 h) group compared to the early PT (12-24 h) group (4.75 vs. 4.96 days, p = 0.009). At 3 months postoperatively, there was no significant difference in ROM, ambulatory distance or functional scores between the < 24 h group and 24-48 h group, or on subgroup analysis of the < 24 h group.

CONCLUSION

Patients who underwent physical therapy within 24 h had a shorter length of stay compared to the 24-48 h group. On subgroup analysis, ultra-early (< 12 h) physical therapy correlated with a shorter length of stay compared to the 12-24 h group (4.75 vs. 4.96 days, p = 0.009) - however, the difference is small and unlikely to be clinically significant. Ultra-early (< 12 h) physical therapy does not confer additional benefit in terms of functional scores, ROM or ambulatory distance. These findings reinforce the importance of early physical therapy after TKA in facilitating earlier patient discharge.

Variation in Utilization of Postoperative Rehabilitation After Total Hip Arthroplasty in Japan

OBJECTIVE

The use of rehabilitation after arthroplasty in Japan is unknown. We aimed to identify utilization of postoperative rehabilitation after total hip arthroplasty (THA) and to explore the factors associated with rehabilitation usage.

DESIGN

A retrospective cohort study using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB).

SETTING

Hospitals nationwide.

PARTICIPANTS

Patients aged >40 years who underwent primary THA between 2017 and 2018 (N=51,332).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The proportion of patients who underwent postoperative rehabilitation and the number of rehabilitation days were also calculated. Patient demographic characteristics, hospital case volumes, and regions associated with continuing postoperative rehabilitation were analyzed using a Cox proportional hazards model.

RESULTS

Eligible patients were selected from 3033 hospitals, of whom 41,192 (80%) were women. Of these, 94% used inpatient rehabilitation, and 20% received outpatient rehabilitation. The mean durations of rehabilitation were 47±72 days for inpatient and 195±109 days for outpatient, respectively. Large-scale hospitals performing more than 200 procedures annually had the shortest duration of inpatient rehabilitation (36-65 days) and the longest duration of outpatient rehabilitation (220-109 days) compared with smaller hospitals. The regression model consistently showed that rehabilitation continued longer at hospitals with over 200 patients per year (HR 0.96, 95% CI 0.93-0.99, P<.007).

CONCLUSION

The Japanese health care system provided higher access to inpatient rehabilitation after THA than other countries. One limitation of this study is that long-term care insurance data were not analyzed. However, outpatient rehabilitation vary according to hospital case volume. Further research is needed to determine the causes of variation in rehabilitation use and the effect of variation on patient outcomes.

Does self-reported physical activity relate to physical function and walking ability in female patients with hip osteoarthritis? A cross-sectional multicenter study

BACKGROUND

The effectiveness of a high level of physical activity in maintaining physical function in patients with hip osteoarthritis has not been adequately examined.

OBJECTIVE

This study aimed to determine whether self-reported physical activity is associated with physical function and walking ability in female patients with hip osteoarthritis.

METHODS

This was a multicenter cross-sectional study. The dependent variables were the lower-limb range of motion and muscle strength, and walking ability. Self-reported physical activity was assessed according to the guidelines of the Japanese Ministry of Health, Labor, and Welfare. Multiple regression models were used to determine whether physical activity was significantly related to the dependent variables after adjusting for confounding factors (age, body mass index, hip pain, comorbidity, and severity of hip osteoarthritis).

RESULTS

A total of 167 participants were included in the study. Physical activity was associated with muscle strength in hip flexion (affected/unaffected, β = 0.18/β = 0.16), abduction (β = 0.19/β = 0.26), knee extension (β = 0.22/β = 0.26), Timed Up-and-Go test (β = -0.16), and 5-m walking time test (β = -0.15).

CONCLUSION

In female patients with hip osteoarthritis, greater physical activity was associated with greater lower extremity muscle strength and walking ability.

Association between Obesity and Short-Term Patient-Reported Outcomes following Total Knee Arthroplasty: A Retrospective Cohort Study in Japan

Background: This study investigated the association between obesity and short-term patient-reported outcomes after total knee arthroplasty (TKA). Methods: The primary outcomes were the Western Ontario and McMaster Universities Osteoarthritis Index's (WOMAC) pain and function scores. Data were collected preoperatively and 2 and 4 weeks after surgery. Patients were stratified into three groups based on body mass index (BMI): normal weight (BMI < 24.99 kg/m2), overweight (25 ≤ BMI < 29.99 kg/m2), and obese (BMI ≥ 30 kg/m2). The associations between BMI and the WOMAC pain and function scores were assessed using generalized linear mixed models. Results: Among the 102 patients (median age: 75.0, women [85.3%]), 29.4%, 48.0%, and 22.5% were normal weight, overweight, and obese, respectively. The mean pain and function scores at baseline were similar across the BMI-stratified groups (p = 0.727 and 0.277, respectively). The pain score significantly improved 2 weeks post-surgery (p = 0.001). The function score improved significantly 4 weeks post-surgery (p < 0.001). The group and group-by-time interaction effects lacked statistical significance. Conclusions: All patients statistically and clinically showed relevant pain reduction and functional improvement shortly after TKA, irrespective of their obesity status. These data may help healthcare professionals discuss the expectations of pain amelioration and functional improvement with TKA candidates.

Comparison of the Effects of Desflurane and Sevoflurane on Variations in Salivary Melatonin and Sleep Disturbance After Total Knee Arthroplasty: A Single-center, Prospective, Randomized, Controlled, Open-label Study

PURPOSE

Anesthesia has been shown to disrupt the circadian rhythm. Recovery of the circadian rhythm after general anesthesia might help alleviate symptoms of insomnia and postoperative delirium. We hypothesized that recovery of the circadian rhythm is faster after total knee arthroplasty (TKA) with desflurane than with sevoflurane. This study compared the influence of sevoflurane versus desflurane anesthesia on the postoperative circadian rhythm of melatonin in adults undergoing TKA.

DESIGN

Single-center, prospective, randomized, controlled, open-label study.

METHODS

This study involved adult patients undergoing TKA at a university hospital in Japan from May 1, 2018 to December 31, 2019. The primary outcome of the study was the comparison of the effect of sevoflurane and desflurane on the circadian rhythm of salivary melatonin for 3 days postoperatively. The secondary outcomes were postoperative fatigue and sleep quality for 3 days postoperatively.

FINDINGS

Twenty-eight patients (American Society of Anesthesiologists physical status of I or II) were scheduled for TKA and randomized to receive sevoflurane (n = 14) or desflurane (n = 14) anesthesia. There was no significant difference in the melatonin concentration between the sevoflurane and desflurane groups. The salivary melatonin concentration after sevoflurane or desflurane anesthesia was significantly higher at 9:00 p.m. on a postoperative day (POD)0 and POD1 than on POD3 (P < .05). Patients in the desflurane group had significantly greater fatigue than those in the sevoflurane group at 7:00 a.m. and 12:00 p.m. on POD3 (P < .05). Patients in the sevoflurane group had a deeper sleep than those in the desflurane group on POD0 (P < .05). In the sevoflurane group, the sleep time during the night of POD2 was longer than that on POD0 (6.1 vs 4.2 hours, P < .05).

CONCLUSIONS

Under the current study conditions, desflurane was equivalent to sevoflurane in terms of the postoperative salivary melatonin concentration and sleep disturbance after TKA but not in terms of recovering the postoperative circadian rhythm.

A Comprehensive Research on the Prevalence and Evolution Trend of Orthopedic Surgeries in Romania

Accurate knowledge of the prevalence and trends of orthopedic surgeries can facilitate the design of medical plans for effective treatments. The National Endoprosthetic Registry (NER) in Romania provides statistics on endoprosthetic activity (hip, knee), cases of fractures and bone tumors as a result of the legal obligations to report interventions performed by all orthopedic traumatology hospitals/wards in the country. The aim of this study is to describe the annual volumes of orthopedic surgeries between 2001 and 2022 in Romania and analyze the current and future evolution trends of the studied surgeries, gender differences and regional differences based on a complete survey carried out at a national level. For the period 2001-2022, we extracted from the NER the annual volumes of orthopedic interventions performed. With these data, we studied the prevalence and estimated, with the support of an original calculation methodology, the variation trends of orthopedic surgeries in two situations: over the entire 21-year period, respectively, and over the period 2001-2020, which does not include the pandemic period. For hip replacement surgery and knee replacement surgery, we showed the prevalence by subcategory of interventions, gender distribution, regional prevalence and regional density calculated by the annual averages of the total number of cases reported per 100,000 people in the 40 counties of the country and the capital, Bucharest. We also determined the variations in hip and knee arthroplasty revision burdens, calculated as a percentage between the number of revisions and the number of primary interventions in the same period. We determined the regional densities of revision burdens. The total number of orthopedic surgeries in the period 2001-2022 was 1,557,247, of which 189,881 were hip replacement surgeries; 51,035 were knee replacement surgeries; 11,085 were revision hip arthroplasty; 1497 were revision knee arthroplasty; 541,440 were operated fractures; and 16,418 were operated bone tumors. The growth rates of surgical interventions are hip replacement surgery, +8.19%; knee replacement surgery, +19.55%; revision hip arthroplasty, +9.43%; and revision knee arthroplasty, +28.57%. With these data, we have estimated a doubling of the volume of primary and revision interventions of the hip until 2034 and the knee until 2027, respectively. Operated bone tumors register an annual decrease of -4.52% thanks to modern treatments. There are clear gender differences; for primary hip interventions, the proportion of women is 58.82%, and for knee interventions, the proportion of women is 76.42%. This is the first research that, with the support of exhaustive data from the NER, analyzes for the period 2001-2022 the annual number of orthopedic surgeries in Romania. It allows knowledge of the large, anticipated increases in orthopedic surgery and provides a quantitative basis for future policy decisions related to the need for medical personnel and material resources.

The State of Microbiology Diagnostic of Prosthetic Joint Infection in Europe: An In-Depth Survey Among Clinical Microbiologists

Background

This study aims to give an overview on how microbiology diagnosis tests of Prosthetic joint infections (PJI) is performed in Europe, and to explore whether any factor influences the decision on implementing a test.

Methods

An extensive online survey of clinical microbiologists from seven European countries (Belgium, Estonia, Germany, Italy, Netherlands, Switzerland, and Spain). Following items were assessed: (i). general information on the laboratory, (ii) preference of the laboratory and clinical microbiologists regarding samples, (iii) transportation and (iv) processing of explanted foreign bodies and tissues and synovial fluid, (v) culture media and culture duration, (vi) reporting (identification and susceptibility testing), and (vii) use of molecular microbiology techniques.

Results

Invited were 163 clinical microbiologists. The response rate from each country was above 50% (range 51-78%), except for Germany (36%). Frequent PJI diagnostics were the use of tissue pre-processing (58.1%), culturing synovial fluid in blood culture bottles (45.5%), use of sonication for processing explanted prosthesis (56.8%), reporting the presence of synovial leukocyte counts (67%), use of blood aerobic and anaerobic agar (97.7%), and enrichment media thioglycolate (69.3%). The most common incubation time of the culture media is 7-14 days (34.1-70.5%). The clinicians were called to report the culture results (80.7%), and to give antibiotic recommendation (67%).

Conclusion

There are common practices in processing PJI samples and reporting results, which is promising for harmonization of PJI diagnostic in the future. However, variation in diagnostic tests should also be considered in interpreting and comparing clinical microbiology results.