To determine risk factors of infection in total knee arthroplasty

This descriptive study was conducted in the Department of Orthopedics for a duration of three years from January 2016 to January 2019. All patients undergoing primary total knee replacement were included in the study. Exclusion criteria were all patients operated in another hospital and revision total knee replacement. All patients were followed up at 2, 4, 8, 12 and 24 weeks post-operatively. Signs of inflammation and inflammatory markers such as total leukocyte count (TLC), C-reactive protein (CRP) and ESR were measured. Risk factors like age, body mass index (BMI), ASA, co-morbid conditions were also noted.

A total of 78 patients underwent primary unilateral Total Knee Replacement (TKR) during the study period. Of these, 30 (34.09%) were male and 48 (61.54%) female patients. Mean age of patients was 68.32 ± 8.54 years. Average BMI 25.89 Kg/m2 .Osteoarthritis was the pre-dominant cause of total knee replacement (94.87%). Among co-morbid factors 33.33% were diabetic, 28.20% having ischemic heart disease and 12.82% with chronic lung disease. Upon anaesthesia fitness pre-operatively, 91.02% patients had an American society of anaesthesiologist score (ASA) between 0–2 while 07 (8.97%) between 3- 5. Average duration of surgery was 85.62± 4.11 minutes. 6.41% cases got infected. In majority of the infected cases (60%), Staphylococcus aureus was the infective organism. Diabetes Mellitus (p=0.01) and Obesity (p=0.02) had a significant relation to post-operative infection.

Pre-operative risk evaluation and prevention strategies along with early recognition of infection and control can greatly reduce the risk of joint infection post-TKR which will not only improve the mobility of patient but also its morbidity and mortality as well.

Key Words:

C-reactive protein (CRP), Erythrocyte Sedimentation Rate (ESR), Staphylococcus aureus, Total Knee Arthroplasty (TKA)

Fracture related infections (FRI) are debilitating complications of musculoskeletal trauma surgery that can result in permanent functional loss or amputation. This study aims to determine risk factors associated with FRI treatment failure, allowing clinicians to optimise them prior to treatment and identify patients at higher risk.

A major trauma centre database was retrospectively reviewed over a six-year period. Of the 102 patients identified with a FRI (66 male, 36 female), 29.4% (n=30) had acute infections (onset <6 weeks post-injury), 34.3% (n=35) had an open fracture. Open fractures were classified using Gustilo-Anderson (GA) classification (type 2:n=6, type 3A:n=16, type 3B:n=10, type 3C:n=3). Patients with periprosthetic infections of the hip and knee joint, those without prior fracture fixation, soft tissue infections, diabetic foot ulcers, pressure sore infections, patients who died within one month of injury, <12 months follow-up were excluded.

FRI treatment failure was defined as either infection recurrence, non-union, or amputation. Lifestyle, clinical, and intra-operative data were documented via retrospective review of medical records. Factors with a P-value of p<0.05 in univariate analysis were included in a stepwise multivariate logistic regression model.

FRI treatment failure was encountered in 35.3% (n=36). The most common FRI site was the femoral shaft (16.7%; n=17), and 15.7% (n=16) presented with signs of systemic sepsis. 20.6% (n=21) had recurrent infection, 9.8% (n=10) had non-union, and 4.9% (n=5) required an amputation. The mean age at injury was 49.71 years old. Regarding cardiovascular risk factors, 37 patients were current smokers (36.3%), 31 patients were diabetics (30.4%), and 32 patients (31.4%) were obese (BMI≥30.0). Average follow-up time was 2.37 (range: 1.04-5.14) years. Risk factors for FRI treatment failure were BMI>30, GA type 3c, and implant retention.

Given that FRI treatment in 35.3% (36/102) ended up in failure, clinicians need to take into account the predictive variables analysed in this study, and implement a multidisciplinary team approach to optimise these factors. This study could aid clinicians to redirect efforts to improve high risk patient management, and prompt future studies to trial adjuvant technologies for patients at higher risk of failure.

Partial meniscectomy patients have a greater likelihood for the development of early osteoarthritis (OA). To prevent the onset of early OA, patient-specific treatment algorithms need to be created that predict patient risk to early OA after meniscectomy. The aim of this work was to identify patient-specific risk factors in partial meniscectomy patients that could potentially lead to early OA.

Partial meniscectomy patients operated between 01/2017 and 12/2019 were evaluated in the study (n=317). Exclusion criteria were other pathologies or surgeries for the evaluated knee and meniscus (n = 114). Following informed consent, an online questionnaire containing demographics and the “Knee Injury and Osteoarthritis Outcome Score” (KOOS) questionnaire was sent to the patient. Based on the KOOS pain score, patients were classified into “low” (> 75) and “high” (< 75) risk patients, indicating risk to symptomatic OA. The “high risk” patients also underwent a follow-up including an MRI scan to understand whether they have developed early OA.

From 203 participants, 96 patients responded to the questionnaire (116 did not respond) with 61 patients considered “low-risk” and 35 “high-risk” patients. Groups that showed a significant increased risk for OA were patients aged > 40 years, females, overweight (BMI >25 kg/m2 ≤ 30 kg/m2), and smokers (*p < 0.05). The “high-risk”-follow-up revealed a progression of early osteoarthritic cartilage changes in seven patients, with the remaining nineteen patients showing no changes in cartilage status or pain since time of operation. Additionally, eighteen patients in the high-risk group showed a varus or valgus axis deviation.

Patient-specific factors for worse postoperative outcomes after partial meniscectomy and indicators for an “early OA” development were identified, providing the basis for a patient-specific treatment approach. Further analysis in a multicentre study and computational analysis of MRI scans is ongoing to develop a patient-specific treatment algorithm for meniscectomy patients.

Background

Orthopedic trauma patients can have significant pain management requirements. Patient satisfaction has been associated with pain control and narcotic use in previous studies. Due to the multifactorial nature of pain, various injury patterns, and differences in pain tolerances the relationship between patient factors and narcotic requirements are poorly understood. The purpose of this study is to compare patient demographics for trauma patients requiring high doses of narcotics for pain control versus those with more minimal requirements.

Background

Nerve Root compression can lead to severe back pain. Different risk factors like high BMI, smoking, alcohol and psychological history have been identified. The aim of our study was to identify if the incidence of these risk factors was higher in patients with nerve root compression.

Background

Post-operative acute kidney injury is significant complication following surgery. Patients who develop AKI have an increased risk for progression into chronic kidney disease, end-stage renal failure and increased mortality risk. The patient outcomes following total knee replacement (TKR), who develop AKI has been a topic of interest in recent years as it may have patient and medicolegal implications. Nevertheless, there are no studies looking at the incidence, risk factors and outcomes of AKI following bilateral TKRs at the same sitting.

High ankle sprains (HAS) cause subtle lesions in the syndesmotic ligaments of the distal tibiofibular joint (DTFJ). Current intrinsic anatomical parameters of the DTFJ are determined based on 2D imaging and uncertainty remains whether they differ in a HAS patients. The aim of this study is therefore two-fold: radiographic parameters will be determined in 3D and compared in a healthy vs sprained group. Ten patients with a mean age of 42,56 (SD = 15,38) that sustained a HAS and twenty-five control subjects with a mean age of 47,44 (SD = 6,55) were retrospectively included. The slices obtained from CT analysis were segmented to have a 3D reconstruction. The following DTFJ anatomical parameters were computed using CAD software: incisura width, incisura depth, incisura length, incisura angle, and incisura-tibia ratio. The mean incisura depth in the sprained group was 3,93mm (SD = 0,80) compared to 4,76 mm (SD = 1,09) in the control group, which showed a significant difference (P < 0.05). The mean incisura length in the group of patients with HAS was 30,81 mm (SD = 3,17) compared to 36,10mm (SD = 5,27) in the control group which showed a significant difference (P < 0.05). The other DTFJ anatomical parameters showed no significant difference. This study shows a significant difference in both incisura depth and incisura length between HAS patients and control subjects. These parameters could be used to identify potential anatomical intrinsic risk factors in sustaining a HAS.

Periprosthetic joint infections (PJIs) are uncommon but are devastating complications of total knee replacement (TKR). We analysed the risk factors of revision for PJI following primary TKR and their association with PJI at different post-operative periods. Primary TKRs and subsequent revision surgeries performed for PJI from 2003–2014 were identified from the National Joint Registry (NJR). Multilevel piece-wise exponential non-proportional hazards models were used to estimate the effect of the investigated factors at different post-operative periods. Patient, perioperative and healthcare system characteristics were investigated and data from the Hospital Episode Statistics for England were linked to obtain information on specific comorbidities. The index TKRs consisted of 679,010 primaries with 3,659 subsequently revised for PJI, 7% within 3 months, 6% between 3–6months, 17% between 6–12months, 27% between 1–2years and 43% ≥2 years from the index procedure. Risk factors for revision for PJI included male sex, high BMI, high ASA grade and young age. Patients with chronic pulmonary disease, diabetes and liver disease had higher risk of revision for PJI, as had patients who had a primary TKR for an indication of trauma or inflammatory arthropathy. Surgical procedure, fixation method, constraint and bearing type influenced the risk of revision for PJI. Their effects were period-specific. No or small associations were found with the operating surgeon grade, surgical volume and hospital surgical volume. These findings from the world's largest joint replacement registry show a more complex picture than the meta-analyses published to date with specific time-dependent effects for the identified risk factors.

UKA with mobile bearing is a one of the treatment of medial osteoarthritis. However, some reports refer to the risk of dislocation of the mobile bearing. Past reports pointed out that medial gap might be enlarged in deep flexion position (over 120 degrees), and says that it will lead to instability of the mobile bearing. The purpose of this study is to research the risk factors of enlargement of medial gap in deep flexion position.

We performed 81 UKAs with mobile bearing system from November 2013 to December 2015, and could evaluate 41 knees. This study of 41 knees included 9 males and 32 females, with average operation age of 75.4years(63–89years). The diagnosis was osteoarthritis in 39 knees and osteonecrosis in 2 knees. The UKA(Oxford partial knee microplasty, Biomet, Warsaw, IN) was used in all cases. We performed distal femur and proximal tibia osteotomy using CT-Free navigation system(Stryker Navigation System II/precision Knee Navigation ver4.0). And we inserted femoral and tibial trial component, then we placed an UKA tensioner on the medial component of the knee. Using tensioner under 30 lbs, we measured joint medial gap at 0,20,45,90,130(deep flexion) degrees. When we compared medial gap at 90 degrees position with at 130 degrees, we defined it as ‘instability group’ if there was gap enlargement more than 1mm, and defined it as ‘stability group’ if there wasn't.

We compared this two groups with regard to age, BMI, femoro-tibial angle (FTA), the diameter of anterior cruciate ligament (ACL), tibial angle and tibial posterior slope angle of the implant. We evaluated preoperative and postoperative FTA by weightbearing long leg antero-posterior alignment view X-rays. We measured ACL diameter at its condyle level in coronal view of MRI. Also we evaluated tibial component implantation angle by postoperative CT using 3D template system. These measurement were analyzed statistically using t test.

The stability group contained 26 knees, and the instability group contained 15 knees. Compared with the stability group, the instability group indicated higher FTA (p=0.001). Between 20 and 90 degrees flexion position, there was no change of medial gap.

Dislocation of the mobile bearing is one of the complications of UKA and it will need re-operation. It is said to be caused by impingement of the bearing and osteophyte of femur. However, some reports said that dislocation was happened when the knee was flexed deeply or twisted, and there was no impingement. We think it may means that dislocation could be caused by medial gap enlargement.

This study indicates that higher FTA could be risk factor of dislocation of mobile bearing. It is important to evaluate preoperatively FTA by X-ray.

Introduction

Achilles tendinopathy (AT) is a highly prevalent injury in athletes and non-athletes with an unknown aetiology. Genetic risk factors have been a recent focus of investigation. The aim of this systematic review was to determine which loci have been linked with mid-portion AT and could potentially be used as biomarkers in tendinopathy risk models or as preventative or therapeutic targets.

Fixed flexion contracture (FFC) following total knee arthroplasty (TKA) is a source of morbidity for patients. This retrospective review of pre- and post-operative data for 811 total knee replacements with two year follow up aimed to identify pre-operative risk factors for developing FFC and quantify the effect of FFC on outcomes. The incidence of FFC two years post-operation was 3.6%. Advanced age was associated with increased rate of FFC (p=0.02) Males were 2.6 times more likely than females to have FFC at two years (p=0.012). Patients with pre-implant FFC were 2.95 times more likely than those without to have FFC (p=0.028). BMI was not a risk factor (p=0.968). Patients with FFC had poorer outcomes (Oxford Knee Score p=0.003, patient satisfaction p=0.036). The results of this study support the existing literature and clarify a previously contentious point by excluding BMI as a risk factor.

Hyponatraemia is one of the most common electrolyte disorders in the elderly and has considerable associated morbidity and mortality. In this study we report the prevalence and independent risk factors for the development of post-operative hyponatraemia after surgery for hip fracture.

We conducted a retrospective cohort study of 144 consecutive patients who underwent surgery after sustaining a hip fracture. Patient medical case-notes, operative notes and online biochemistry results were used to obtain relevant data which was entered into a database.

Pre-operative (30/144, 21%) and post-operative hyponatraemia (49/144, 34%) was common. However, most cases were mild (plasma sodium >130 mmol/l) and only 1% of pre-operative and 6% of post-operative patients had moderate/severe hyponatraemia (plasma sodium <130mmol/l). One of 3 post-operative deaths involved a patient with moderate hyponatraemia as a consequence of severe congestive cardiac failure. In order to determine the independent relationship between several reported risk factors and hyponatraemia we constructed a multivariable logistic regression model. Female gender, pre-operative hyponatraemia and hypotonic fluid administration were all significantly associated with the development of post-operative hyponatraemia. Age and thiazide diuretics both had positive risk associations however were not statistically significant.

Hyponatraemia is a common problem in hip fracture patients. While the majority of cases in this series were mild, 6% of patients suffered from moderate/severe hyponatraemia post-operatively. Female gender, pre-operative hyponatraemia and hypotonic fluid administration are all important and independent risk factors for the development of hyponatraemia. Hypotonic intravenous fluids should be avoided unless clinically indicated in this patient group.

Introduction

Numerous risk factors have been identified for patellar tendinopathy (PT), often in small population studies. The aim was to use an online questionnaire internationally to generate a large database and identify significant risk factors.

Worldwide, osteoporosis, causes more than 8.9 million fractures annually, resulting in an osteoporotic fracture every 3 seconds, where 1 in every 3 women and 1 in every 5 men aged over 50 will experience osteoporotic fractures at least once in their lifetime. Vertebral fractures, estimated at 1.4 million/year are among the most common fractures, posing enormous health and socioeconomic challenges to the individual and society at large. Considering that the great majority of individuals at high risk (up to 80%), who have already had at least one osteoporotic fracture, are neither identified nor treated, prediction of the risk factors for vertebral fractures can be of great value for prevention/early diagnosis. Recent studies show that finite element analysis of computed tomography (CT) scans provides noninvasive means to assess fracture risk and has the potential to be clinically implemented upon proper validation. The objective of this study was to develop a voxel-based finite element model using quantitative computed tomography (QCT) images in conjunction with in-vitro experiments to evaluate the strength of the vertebral bodies and predict the fracture risk criteria. A total of 10 vertebrae were dissected from juvenile sheep lumbar spines. The attached soft tissues and posterior elements and facet joints were completely removed, and the upper and lower vertebral bodies were polished using glass paper to provide smooth surfaces. The specimens were wrapped in phosphate buffer saline (PBS) soaked gauze, sealed in plastic bags, and stored in a refrigerator at −22°C. QCT scans of the specimens were captured using a bone density calibration phantom (QRM Co., Moehrendorf, Germany) with three 18 mm cylindrical inserts, providing 0, 100 and 200 mg HA/ccm, respectively. All the specimens, preserved hydrated in PBS solution, were mechanically tested at room temperature using a mechanical testing apparatus (Zwick/Roell, Ulm-Germany). The QCT images were then used to reconstruct the voxel-based FE model employing a custom-developed heterogeneous material mapping code. Five different equations for the correlation of the density and the elastic modulus were used to validate the efficiency of the FE model as compared to the in-vitro experiments. The results of the voxel-based FE models matched well with the in-vitro experiments, with an average error of 11.38 (±4.09)% based on the power law equation. A failure criterion was embedded in the FE models and the initiation of fracture was successfully predicted for all specimens. Further, typical kyphoplasty treatment was simulated in the 5 models to evaluate the application of the validated algorithm in the estimation of the failure patterns. Our novel voxel-based FE model can be used in future studies to predict the outcome of different types of therapeutic modalities/surgeries and estimate fracture risk including postoperative fractures.

Introduction

Prosthetic joint infection (PJI) is an uncommon but serious complication of hip replacement.

A recent systematic review of patient risk factors for PJI identified male gender, smoking status, increasing BMI, steroid use, previous joint surgery and comorbidities of diabetes, rheumatoid arthritis and depression as risk factors for developing PJI. Limitations of the current literature include the short term follow up of most published studies.

We investigated the role of patient, surgical and healthcare factors on the risk of revision of a primary hip replacement for PJI at different time-points in the post-operative follow-up. It is important that those risk factors are identified so that patients can be appropriately counselled according to their individual risk profile prior to surgery and modifiable factors can be addressed to reduce the risk of PJI at an individual and healthcare system level.

Summary Statement

Tandem stenosis is a prevalent condition in an Asian population with the narrowest cervical canal diameters and risk factors include advanced age and increased levels of lumbar canal stenosis.

Introduction

The goal of joint-preserving surgery for the treatment of osteonecrosis of the femoral head (ONFH) is to delay or prevent osteoarthritic development. Bone marrow is a source of osteogenic progenitors that are key elements in the process of bone formation and fracture healing. We established an easy-to-use method using a conventional manual blood bag centrifugation technique traditionally used for extracting buffy coats, for concentration of nucleated cells and platelets from clinical bone marrow aspirates to obtain osteogenic progenitors and growth factors. However, it is unclear whether the surgical goals are really achieved and if so in which patients. The purpose of this study was to identify demographic, clinical, and radiographic factors predicting total hip arthroplasty (THA) conversion after CABMAT for the treatment of idiopathic ONFH.