Periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) is a devastating complication. It is associated with high morbidity and mortality. It remains, unfortunately, one of the most common modes of failure in TKA. Much attention has been paid to the treatment of PJI once it occurs. Our attention, however, should focus on how to reduce the risk of PJI from developing in the first place. Infection prevention should focus on reducing modifiable risk factors that place patients at increasing risk for developing PJI. These areas include pre-operative patient optimization and intra-operative measures to reduce risk. Pre-operative Modifiable Risk Factors: There are several patient related factors that have been shown to increase patient's risk of developing PJI. Many of these are modifiable risk factors can and should be optimised prior to surgery. Obesity and in particular Morbid Obesity (BMI >40) has a strong association with increased risk of PJI. Appropriate and healthy weight loss strategies should be instituted prior to elective TKA. Uncontrolled Diabetes (Hgb A1C >8) and poor glycemic control around the time of surgery increases the risk for complications, especially PJI. Malnutrition should be screened for in at-risk patients. Low Albumin levels are a risk factor for PJI and should be corrected. Patients should be required to stop smoking 6 weeks prior to surgery to lower risk. Low Vitamin D levels have been show to increase risk of PJI. Reduction of colonization of patient's nares with methicillin sensitive (MSSA) and resistant (MRSA) staphylococcus should be addressed with a screen and treat program. Intra-operative Measures to Reduce PJI: During surgery, several steps should be taken to reduce risk of infection. Appropriate dosing and timing of antibiotics is critical and a first generation cephalosporin remains the antibiotic of choice. The use of antibiotic cement remains controversial with regards to its PJI prophylactic effectiveness. The utilization of a dilute betadine lavage has demonstrated decreased rate of PJI. Maintaining normothermia is critical to improve the body's ability to fight infection. An alcohol-based skin preparation can reduce skin flora as a cause of PJI. Appropriate selection of skin incisions and soft tissue handling can reduce wound healing problems and reduce development of PJI. Likewise, the use of occlusive dressing has been shown to promote wound healing and reduce PJI rates

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)

Aim

Prosthetic joint replacement is more commonly done in the elderly group of patients due to an increase pathology related to joint degeneration that comes with age. In this age group is also more frequent having underling condition that may predispose to a prosthetic joint infection. Also, the pharmacological intervention in those patients may play an important role as a risk factor for infection after joint replacement surgery. The use of oral anticoagulants seems to be particularly increased in elderly patients but there aren't enough data published to support an association between prosthetic joint infection and the use of oral anticoagulants.

Identifying risk factors in elderly patients age >75 years old with a special focus on the oral anticoagulation therapy is the aim of the study.

Iliopsoas impingement occurs in between 5–30% of patients after hip arthroplasty and has been thought to only be caused by an oversized cup, cup malpositioning, or the depth of the psoas valley. However, no study has associated the relationship between preoperative measurements with the risk of impingement. This study sought to assess impingement between the iliopsoas and acetabular cup using a novel validated model to determine the risk factors for iliopsoas impingement.

413 patients received lower limb CT scans and lateral x-rays that were segmented, landmarked, and measured using a validated preoperative planning protocol. Implants were positioned according to the preference of ten experienced surgeons. The segmented bones were transformed to the standing reference frame and simulated with a novel computational model that detects impingement between the iliopsoas and acetabular cup. Definitions of patients at-risk and not at-risk of impingement were defined from a previous validation study of the simulation. At-risk patients were propensity score matched to not at-risk patients.

21% of patients were assessed as being at-risk of iliopsoas impingement. Significant differences between at-risk patients and not at-risk patients were observed in standing pelvic tilt (p << 0.01), standing femoral internal rotation (p << 0.01), medio-lateral centre-of-rotation (COR) change (p << 0.01), supine cup anteversion (p << 0.01), pre- to postoperative cup offset change (p << 0.001), postoperative gross offset (p = 0.009), and supero-inferior COR change (p = 0.02).

Impingement between the iliopsoas and acetabular cup is under-studied and may be more common than is published in the literature. Previously it has been thought to only be related to cup size or positioning. However, we have observed significant differences between at-risk and not at-risk patients in additional measurements. This indicates that its occurrence is more complex than simply being related to cup position.

Arthrofibrosis is a less common complication following anterior cruciate ligament (ACL) reconstruction and there are concerns that undergoing early surgery may be associated with arthrofibrosis. The aim of this study was to identify the patient and surgical risk factors for arthrofibrosis following primary ACL reconstruction.

Primary ACL reconstructions prospectively recorded in the New Zealand ACL Registry between April 2014 and December 2019 were analyzed. The Accident Compensation Corporation (ACC) database was used to identify patients who underwent a subsequent reoperation with review of operation notes to identify those who had a reoperation for “arthrofibrosis” or “stiffness”. Univariate Chi-Square test and multivariate Cox regression analysis was performed. Hazard ratios (HR) with 95% confidence intervals (CI) were computed to identify the risk factors for arthrofibrosis.

9617 primary ACL reconstructions were analyzed, of which 215 patients underwent a subsequent reoperation for arthrofibrosis (2.2%). A higher risk of arthrofibrosis was observed in female patients (adjusted HR = 1.67, 95% CI 1.22 – 2.27, p = 0.001), patients with a history of previous knee surgery (adjusted HR = 1.97, 95% CI 1.11 – 3.50, p = 0.021) and when a transtibial femoral tunnel drilling technique was used (adjusted HR = 1.55, 95% CI 1.06 – 2.28, p = 0.024). Patients who underwent early ACL reconstruction within 6 weeks of their injury did not have a higher risk of arthrofibrosis when compared to patients who underwent surgery more than 6 weeks after their injury (3.5% versus 2.1%, adjusted HR = 1.56, 95% CI 0.97 – 2.50, p = 0.07). Age, graft type and concomitant meniscal injury did not influence the rate of arthrofibrosis.

Female sex, a history of previous knee surgery and a transtibial femoral tunnel drilling technique are risk factors for arthrofibrosis following primary ACL reconstruction.

Aims

Despite numerous studies on periprosthetic joint infections (PJI), there are no robust data on the risk factors and timing of metachronous infections. This study was performed to answer the following questions: 1) Is there any difference of manifestation time of metachronous PJIs between different localizations of multiple artificial joints? 2) Can we identify any specific risk factor for metachronous PJIs for different localizations of multiple artificial joints?

Aim

Sepsis is a life-threatening complication of periprosthetic joint infections (PJI) that requires early and effective therapy. This study aims to investigate the epidemiology, associated risk factors, and outcome of sepsis in the context of periprosthetic joint infections (PJI).

Aim

Ankle fracture surgery comes with a risk of fracture-related infection (FRI). Identifying risk factors are important in preoperative planning, in management of patients, and for information to the individual patient about their risk of complications. In addition, modifiable factors can be addressed prior to surgery. The aim of the current paper was to identify risk factors for FRI in patients operated for ankle fractures.

Psoas tendinopathy is a potential cause of groin pain after primary total hip arthroplasty (THA). The direct anterior approach (DAA) is becoming increasingly popular as the standard approach for primary THA due to being a muscle preserving technique. It is unclear what the prevalence is for the development of psoas-related pain after DAA THA, how this can influence patient reported outcome, and which risk factors can be identified.

This retrospective case control study of prospectively recorded data evaluated 1784 patients who underwent 2087 primary DAA THA procedures between January 2017 and September 2019. Psoas tendinopathy was defined as (1) persistence of groin pain after DAA THA and was triggered by active hip flexion, (2) exclusion of other causes such as dislocation, infection, implant loosening or (occult) fractures, and (3) a positive response to an image-guided injection with xylocaine and steroid into the psoas tendon sheath. Complication-, re-operation rates, and patient-reported outcome measures (PROMs) were measured.

Forty-three patients (45 hips; 2.2%) were diagnosed with psoas tendinopathy according to the above-described criteria. The mean age of patients who developed psoas tendinopathy was 50.8±11.7 years, which was significantly lower than the mean age of patients without psoas pain (62.4±12.7y; p<0.001). Patients with primary hip osteoarthritis were significantly less likely to develop psoas tendinopathy (14/1207; 1.2%) in comparison to patients with secondary hip osteoarthritis to dysplasia (18/501; 3.6%) (p<0.001) or FAI (12/305; 3.9%) (p<0.001). Patients with psoas tendinopathy had significantly lower PROM scores at 6 weeks and 1 year follow-up.

Psoas tendinopathy was present in 2.2% after DAA THA. Younger age and secondary osteoarthritis due to dysplasia or FAI were risk factors for the development of psoas tendinopathy. Post-operatively, patients with psoas tendinopathy often also presented with low back pain and lateral trochanteric pain. Psoas tendinopathy had an important influence on the evolution of PROM scores.

The optimal timing of when to perform manipulation under anesthesia (MUA) for stiffness following total knee arthroplasty (TKA) is unclear. This study aimed to identify the risk factors for MUA following primary TKA and whether performing an “early” MUA within 3 months results in a greater improvement in range of motion.

Primary TKAs performed between January 2013 and December 2018 at three tertiary New Zealand hospitals were reviewed. International Classification of Diseases discharge coding was used to identify patients who underwent an MUA. Multivariate Cox regression was performed to identify patient and surgical risk factors for MUA. Pre- and post-MUA knee flexion angles were identified through manual review of operation notes. Multivariate linear regression was performed to compare the mean flexion angles pre- and post-MUA, as well as the mean gain in flexion, between patients undergoing “early” (<3 months) versus “late” MUA (>3 months).

7386 primary TKAs were analyzed in which 131 underwent subsequent MUA (1.8%). Patients aged <65 years were two times more likely to undergo MUA compared to patients aged ≥65 years (2.5% versus 1.3%, adjusted hazard ratio = 2.1, p<0.001). Gender, body mass index, patient comorbidities or a history of cancer were not associated with the risk of MUA. There was no difference in the final post-MUA flexion angle between patients who underwent early versus late MUA (104.7 versus 104.1 degrees, p = 0.819). However, patients who underwent early MUA had poorer pre-MUA flexion (72.3 versus 79.6 degrees, p = 0.012), and subsequently had a greater overall gain in flexion compared to patients who underwent late MUA (mean gain 33.1 versus 24.3 degrees, p<0.001).

Younger age was the only patient risk factor for MUA. A greater overall gain in flexion was achieved in patients who underwent early MUA within 3 months.

Introduction

Selective screening of children at risk for developmental dysplasia of the hip (DDH) is based on clinical examination and risk factor identification. Two meta-analyses published in 2012 found breech presentation, family history of DDH, female sex and primiparity to increase the risk of DDH. However, the DDH definition, reference tests and age of the examined children vary considerably, complicating the translation of those findings to current screening guidelines. The aim of this meta-analysis was to evaluate the association of previously proposed risk factors to the risk of sonographically verified DDH.

Aims

Using the Australian and New Zealand Hip Fracture Registry (ANZHFR) data, this study aimed to identify patient, fracture, and management factors associated with survival, mobility and residential status at 120 days. This will allow future interventions to target modifiable risk factors to improve the overall care of patients with hip fractures.

Developmental dysplasia of the hip can cause pain and premature osteoarthritis. However, the risk factors and timing for disease progression in young adults are not fully defined. This study identified the incidence and risk factors for contralateral hip pain and surgery after periacetabular osteotomy (PAO) on an index dysplastic hip.

Patients followed for 2+ years after unilateral PAO were grouped by eventual contralateral pain or no-pain, based on modified Harris Hip Score, and surgery or no-surgery. Univariate analysis tested group differences in demographics, radiographic measures, and range-of-motion. Kaplan-Meier survival analysis assessed pain development and contralateral hip surgery over time. Multivariate regression identified pain and surgery risk factors. Pain and surgery predictors were further analyzed in Dysplastic, Borderline, and Non-dysplastic subcategories, and in five-degree increments of lateral center edge angle (LCEA) and acetabular inclination (AI).

184 patients were followed for 4.6±1.6 years, during which 51% (93/184) reported hip pain and 33% (60/184) underwent contralateral surgery. Kaplan-Meier analysis predicted 5-year survivorship of 49% for pain development and 66% for contralateral surgery. Painful hips exhibited more severe dysplasia than no-pain hips (LCEA 16.5º vs 20.3º, p<0.001; AI 13.2º vs 10.0º p<0.001). AI was the sole predictor of pain, with every 1° AI increase raising the risk by 11%. Surgical hips also had more severe dysplasia (LCEA 14.9º vs 20.0º, p<0.001; AI 14.7º vs 10.2º p<0.001) and were younger (21.6 vs 24.1 years, p=0.022). AI and a maximum alpha angle ≥55° predicted contralateral surgery.

5 years after index hip PAO, 51% of contralateral hips experience pain and 34% percent are expected to need surgery. More severe dysplasia, based on LCEA and AI, increases the risk of contralateral hip pain and surgery, with AI being a predictor of both outcomes. Knowing these risks can inform patient counseling and treatment planning.

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.

The aim of this study was to determine the incidence, annual trend, perioperative outcomes, and identify risk factors of early-onset (≤ 90 days) deep surgical site infection (SSI) following primary total knee arthroplasty (TKA) for osteoarthritis. Risk factors for early-onset deep SSI were assessed.

We performed a retrospective population-based cohort study using prospectively collected patient-level data from several provincial administrative data repositories between January 2013, and March 2020. The diagnosis of early-onset deep SSI was based on published Centre for Disease Control/National Healthcare Safety Network (CDC/NHSN) definitions. The Mann-Kendall Trend Test was used to detect monotonic trends in early-onset deep SSI rates over time. The effects of various patient and surgical risk factors for early-onset deep SSI were analyzed using multiple logistic regression. Secondary outcomes were 90-day mortality and 90-day readmission.

A total of 20,580 patients underwent primary TKA for osteoarthritis. Forty patients had a confirmed deep SSI within 90-days of surgery representing a cumulative incidence of 0.19%. The annual infection rate did not change over the 7-year study period (p = 0.879). Risk factors associated with early-onset deep SSI included blood transfusions (OR, 3.93 [95% CI 1.34-9.20]; p=0.004), drug or alcohol abuse (OR, 4.91 [95% CI 1.85-10.93]; p<0.001), and surgeon volume less than 30 TKA per year (OR, 4.45 [1.07-12.43]; p=0.013). Early-onset deep SSI was not associated with 90-days mortality (OR, 11.68 [0.09-90-58]; p=0.217), but was associated with an increased chance of 90-day readmission (OR, 50.78 [26.47-102.02]; p<0.001).

This study establishes a reliable baseline infection rate for early-onset deep SSI after TKA for osteoarthritis through the use of a robust methodological process. Several risk factors for early-onset deep SSI are potentially modifiable or can be optimized prior to surgery and be effective in reducing the incidence of early-onset SSI. This could guide the formulation of provincial screening programs and identify patients at high risk for SSI.

Introduction

Weight is a modifiable risk factor for osteoarthritis (OA) progression. Despite the emphasis on weight loss, data quantifying the changes seen in joint biomechanics are limited. Bariatric surgery patients experience rapid weight loss. This provides a suitable population to study changes in joint forces and function as weight changes.

Known risk factors for early periprosthetic femur fracture (PFF) following total hip arthroplasty (THA) include poor bone quality, surgical approach and cementless implants. The association between femoral component size and alignment and the risk of early PFF is not well described. We evaluated radiographic parameters of femoral component sizing and alignment as risk factors for early PFF.

From 16,065 primary cementless THA, we identified 66 cases (0.41%) of early PFF (<90 days from index THA) at a single institution between 2016–2020. The stem was unstable and revised in all cases. We matched 60 cases of early PFFs (2:1) to 120 controls based on femoral component model, offset, surgical approach, age, BMI, and sex. Mean age was 67 years; 60% were female. Radiographic assessment of preoperative bone morphology and postoperative femoral component parameters including stem alignment, metaphyseal fill, and medial congruence with the calcar. A multivariable logistic regression was built to identify radiographic risk factors associated with early PPF.

Markers of poor preoperative bone quality including canal calcar ratio (p=0.003), canal flare index (p<0.001), anteroposterior canal bone ratio (CBR) (p<0.001) and lateral CBR (p<0.001) were statistically associated with PFF. Valgus alignment (23% versus 12%) (p<0.001) was more prevalent in the PFF group compared to controls, as well as varus alignment of the implant (57% versus 43%). Distance between the medial aspect of the implant and the calcar was greater in cases of PFF (2.5 mm versus 1.4 mm) (p<0.001). Multivariate analysis demonstrated that valgus implant alignment (Odds Ratio (OR) 5) and medial implant-calcar incongruity (OR 2) increased the risk of early PFF.

Medial implant-calcar incongruity and valgus alignment of the femoral component were risk factors for early PFF following cementless THA after controlling for age, sex, BMI, approach, proximal femoral morphology, and implant design.

Aim

Acute post-surgical infection is one of the most serious complications after instrumented thoracolumbar fusion with an incidence of 0.7%-12%. Acute infection can lead to an increase in morbidity, mortality, and economic costs for the healthcare system.

The main objective of our study was to determine the variables associated with a higher risk of acute infection after thoracolumbar instrumentation in our center.

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.

Primary total joint arthroplasty (TJA) is an increasingly common and safe way of treating joint disease. Robust preoperative assessment improved intraoperative techniques and holistic rehabilitation contribute to an uneventful postoperative period. Despite there being evidence against the utility of postoperative blood tests, it is still often part of routine practice. We aim to evaluate the usefulness of these tests by investigating their incidence following TJA as well as identifying preoperative risk factors for abnormal blood test results postoperatively especially pertaining to anaemia and acute kidney injury (AKI).

This is a retrospective cohort study of patients who had elective TJA between January and December 2019 at a tertiary centre. An independent student's t-test and Fisher's exact test was used to compare variables between the normal and abnormal postoperative results groups. An analysis of variance (ANOVA) was performed to identify risk factors for an abnormal blood test result. Analyses of receiver operating characteristic (ROC) curves and the area under the curve (AUC) were used to determine cut off values that could be suggestive of abnormal test results postoperatively.

The study included 2721 patients with a mean age of 69 of which 46.6% were males. Abnormal postoperative bloods were identified in 444 (16.3%) patients. We identified age (≥65 years), female gender, ASA ≥ 3 as risk factors for developing abnormal postoperative blood tests. Preoperative haemoglobin (≤ 127 g/dL), haematocrit (≤ 0.395L/L) and potassium (≤ 3.7 mmol/L) were noted as cut-offs that could be predictive of postoperative anaemia or AKI respectively.

The costs outweigh the benefits of ordering routine postoperative blood tests in TJA patients. Clinicians should risk stratify their patients and have a lower threshold for ordering blood tests in patients with one or more of the risk factors we have identified. These risk factors are age (≥65 years), females, ASA ≥ 3, preoperative haemoglobin (≤ 127 g/L), haematocrit (≤ 0.395L/L), and potassium (≤ 3.7 mmol/L).