Obesity in total hip arthroplasty

Body Mass Index Does Not Drive the Risk for Early Postoperative Instability After Total Hip Arthroplasty: A Matched Cohort Analysis

BACKGROUND

Instability remains the leading cause of revision following total hip arthroplasty (THA). The objective of the present investigation was to determine whether an elevated body mass index (BMI) is associated with an increased risk of instability after primary THA.

METHODS

An administrative claims database was queried for patients undergoing elective, primary THA for osteoarthritis between 2010 and 2022. Patients who underwent THA for a femoral neck fracture were excluded. Patients who had an elevated BMI were grouped into the following cohorts: 25 to 29.9 (n = 2,313), 30 to 34.9 (n = 2,230), 35 to 39.9 (n = 1,852), 40 to 44.9 (n = 1,450), 45 to 49.9 (n = 752), and 50 to 59.9 (n = 334). Patients were matched 1:1 based on age, sex, and Elixhauser Comorbidity Index, as well as a history of spinal fusion, neurodegenerative disorders, and alcohol abuse, to controls with a normal BMI (20 to 24.9). A multivariate logistic regression controlling for age, sex, Elixhauser Comorbidity Index, and additional risk factors for dislocation was used to evaluate dislocation rates at 30 days, 90 days, 6 months, 1 year, and 2 years. Rates of revision for instability were similarly compared at 1 year and 2 years postoperatively.

RESULTS

No significant differences in dislocation rate were observed between control patients and each of the evaluated BMI classes at all evaluated postoperative intervals (all P values > .05). Similarly, the risk of revision for instability was comparable between the normal weight cohort and each evaluated BMI class at 1 year and 2 years postoperatively (all P values > .05).

CONCLUSIONS

Controlling for comorbidities and known risk factors for instability, the present analysis demonstrated no difference in rates of dislocation or revision for instability between normal-weight patients and those in higher BMI classes.

Short stem hip arthroplasty with the optimys prosthesis is a safe and effective option for obese patients: a mid-term follow-up multicenter study

INTRODUCTION

Short stems are a valuable option in young patients undergoing total hip arthroplasty (THA) because of their bone stock preserving properties facilitating revision hip arthroplasty. Although the effect of obesity on conventional THA is well studied, data about short stem THA in obese patients are lacking. Therefore, this study aimed to investigate the influence of obesity on complications, revisions, and outcome after short stem THA.

MATERIALS AND METHODS

This multicenter, observational cohort study included patients undergoing short stem THA with the optimys prosthesis. Follow-up examinations were performed at specific intervals up to 7 years postoperatively. Operation characteristics, general and specific complications, revisions, VAS rest pain, VAS load pain, VAS patient satisfaction, and Harris Hip Score (HHS) were recorded and statistically compared between obese (BMI ≥ 30 kg/m2) and non-obese (BMI < 30 kg/m2) patients.

RESULTS

Of the 224 patients included with a mean follow-up of 87.2 months (range 81.9-104.0), 69 were assigned to the OB group and 155 to the non-OB group. A minimally invasive approach was significantly less often selected in obese patients (p = 0.049), whereas operating time and length of hospital stay were not significantly different. The rate of general and specific complications did not significantly differ between both groups. Survival of the optimys prosthesis was 99.1% at 7-year follow-up and one patient per group had to undergo revision surgery. VAS rest pain, load pain, and satisfaction improved from preoperatively to postoperatively in both groups without a significant difference between both groups. While the HHS was improved from preoperatively to postoperatively, obese patients showed a significantly lower HHS at the 7-year follow-up (p = 0.01) but still exhibited an excellent scoring above the PASS threshold.

CONCLUSION

Short stem THA with the optimys prosthesis is a safe and effective option also in obese patients with an excellent clinical outcome and a low complication rate.

Impact of Demographic Variables on Recovery After Total Hip Arthroplasty

BACKGROUND

Several patient factors affect recovery after total hip arthroplasty (THA). However, the impact of these variables on patient-reported outcome measure recovery curves following THA has not been defined. Our goal was to quantify the influence of multiple variables on recovery after primary THA.

METHODS

There were 1,724 patients in a multicenter study included. Variables included sex, race/ethnicity, anxiety/depression, body mass index, tobacco, and preoperative opioid use. The Hip disability and Osteoarthritis Score for Joint Replacement (HOOS JR) was recorded at multiple time points. Recovery curves were created using longitudinal estimating equations.

RESULTS

Patients who were women, obese, or smokers demonstrated lower HOOS JR scores at all time points. Preoperative opioid use was also correlated with lower HOOS JR scores, but this difference diminished after 6 months. Black patients demonstrated lower HOOS JR scores compared to Caucasians, and this relative difference increased out to 1-year postoperatively (P = .018). Hispanics also had lower HOOS JR scores, but scores recovered at similar rates compared to non-Hispanics. Patients who had only anxiety or depression had similar HOOS JR scores compared to patients who did not have anxiety or depression. However, patients who had both anxiety and depression had lower HOOS JR scores compared to patients who had neither (P = .049), and this relative difference became greater at 1-year postoperatively (P = .002).

CONCLUSIONS

Several factors including race/ethnicity, opioid use, and mental health influence recovery trajectory following THA. This information helps provide more individualized counseling about expectations after THA and focus targeted interventions to improve outcomes in at-risk groups.

While the Incidence of Venous Thromboembolism After Shoulder Arthroscopy Is Low, the Risk Factors Are a Body Mass Index Greater than 30 and Hypertension

Purpose

This study aims to determine the overall incidence of venous thromboembolism (VTE) following shoulder arthroscopy and to define potential risk factors associated with its development that may help define guidelines for the use of thromboprophylaxis.

Methods

A systematic review was performed using PubMed, Embase, Web of Science, CINAHL, and Cochrane databases per PRISMA guidelines. The search terms consisted of variations of "Venous Thromboembolism" and "Shoulder Arthroscopy." Information regarding arthroscopy indication, risk factors, outcomes, and patient demographics was recorded and analyzed, and pooled odds ratios were reported for each variable.

Results

Six hundred eighty-five articles were identified in the initial search, and 35 articles reported DVT, PE, or VTE incidence following shoulder arthroscopy. Seventeen nonoverlapping articles with a unique patient population incidence rates. Four articles were then used for subgroup meta-analysis. The incidence rate of VTE was 0.24%, ranging from 0.01% to 5.7%. BMI >30 (OR = 1.46; 95% CI = [1.22, 1.74]; I2 = 0%) and hypertension (OR = 1.64; 95% CI = [1.03, 2.6]; I2 = 75%) were significant risk factors (P < .05) for developing VTE following shoulder arthroscopy. Diabetes (OR = 1.2; 95% CI = [0.97, 1.48]; I2 = 0%), insulin-dependent diabetes (OR = 5.58; 95% CI = [0.12, 260.19]; I2 = 85%), smoking (OR = 1.04; 95% CI = [0.79, 1.37]; I2 = 12%), male sex (OR = 0.95; 95% CI = [0.49, 1.85]; I2 = 86%) and age over 65 (OR = 4.3; 95% CI = [0.25, 72.83]; I2 = 85%) were not associated with higher VTE risk.

Conclusion

The VTE incidence following shoulder arthroscopy is low at 0.24%. Patients with BMI >30 and hypertension are at a higher risk for VTE after shoulder arthroscopy.

Level of Evidence

Level IV, systematic review and meta-analysis of Level I-IV studies.

The Effect of Obesity on Hemiarthroplasty and Total Hip Arthroplasty for Femoral Neck Fractures

Obesity is a well-recognized global epidemic that can lead to longer operative times as well as a greater technical demand. Despite this, the available literature evaluating the impact of obesity on hip hemiarthroplasty (HA) and total hip arthroplasty (THA) when treating fractures about the femoral neck is scarce. Between 2015 and 2018, we retrospectively reviewed all patients that had a HA or THA performed as treatment for an isolated fracture of the femoral neck. Patients were classified as obese and nonobese depending on current body mass index (BMI) when the index procedure was performed. Preoperative and postoperative variable were obtained from the electronic medical record. A total of 157 patients underwent hip HA or THA for an isolated fracture of the femoral neck. In those patients undergoing HA, obesity was associated with an increase in operative times (P = 0.021) and was associated with a nonsignificant increase in total operating room time (P = 0.088) and duration of anesthesia (P = 0.14). In those patients undergoing THA, obesity was associated with longer operative times (P = 0.043), total operating room time (P = 0.032), and duration of anesthesia (P = 0.045). There were no significant differences in complication rates postoperatively between obese and non-obese patients undergoing either procedure. The treatment of isolated fractures of the femoral neck with HA or THA leads to an increase in operative time without an increase in postoperative complications in obese patients.

Impact of wound complications in obese versus non-obese patients undergoing total hip arthroplasty: A meta-analysis

This meta-analysis examined the post-operative wound effect of both obese and non-obese in total hip arthroplasty (THA) patients. To gather as complete an overview as possible, the researchers took advantage of 4 databases-PubMed, Embase, Cochrane Library and Web of Science-to conduct a critical assessment. Following the development of inclusion and exclusion criteria, the researchers evaluated the quality of each document. A total of 9 related trials were conducted to determine the 95% CI (CI) and OR using a fixed-effect model. The final meta-analyses were conducted with RevMan 5.3. Our findings indicate that there is no statistically significant benefit in terms of post-operative wound complications among obese and non-obese patients. Obese subjects had a significantly higher risk of injury than those without obesity (OR, 1.43; 95% CI, 1.04, 1.95, p = 0.03); obesity was also associated with a significantly higher risk of operative site infection than in non-obese subjects (OR, 1.96; 95% CI, 1.76, 2.18, p < 0.0001); and after surgery, there was also a significant increase in the risk of post-operative wound infections among obese subjects than in non-obese subjects (OR, 1.57; 95% CI, 1.34, 1.84, p < 0.0001). However, due to the small size of the cohort study in this meta-study, caution is required in the analysis. More randomized, controlled studies will be needed to validate these results.

Bariatric surgery prior to total hip arthroplasty: does timing or type matter?

INTRODUCTION

Morbid obesity is a known risk-factor for increased complications following total hip arthroplasty (THA). Thus, many orthopaedic surgeons recommend bariatric surgery (BS). However, there is no consensus on the type (commonly either a Roux-en-Y gastric bypass [RYGB] or sleeve gastrectomy [SG]) and timing of BS prior to THA. Therefore, the purpose of this study is to compare BS recipients prior to THA to assess differences in 90-day to 2-year medical/surgical complications as well as revisions for: (1) type of BS (RYGB and SG); and (2) timing of BS. Additionally, we aim to assess risk factors for postoperative prosthetic joint infections (PJIs), dislocations, and revisions.

METHODS

We queried a national, all-payer database to identify patients undergoing primary THA from January 2010 to October 2020 (n = 715,100). Patients were then divided into 6 cohorts: 2 cohorts without history of BS (body mass index [BMI] kg/m2 20-35 [n = 59,995]) and BMI > 40 [n = 36,799]); 2 cohorts with previous RYGB (n = 1278) or SG (n = 1051); and 2 cohorts that underwent BS either 6-12 months (n = 412) and >12 months (n = 1655) prior to the THA. Bivariate chi-square analyses of medical and surgical outcomes at 90 days-2 years were conducted. Multivariate logistic regressions identified independent risk factors for PJIs, dislocations, and revisions.

RESULTS

At 90 days-2 years, no differences in postoperative medical/surgical complications or revisions were seen among timing or type of BS. The BMI > 40 kg/m2 cohort had the highest complication profile among all other cohorts. Timing and type of BS has similar odds of PJIs, dislocations, and revisions.

CONCLUSIONS

Patients undergoing RYGB or SG 6-12 months and >1 year prior to THA showed similar complications profiles. These results suggest, bariatric patients do not need to wait 1 year before undergoing a THA.

Are self-reported anthropometric data reliable enough to meet antibiotic prophylaxis guidelines in orthopedic surgery?

BACKGROUND

Surgical site infection is a serious complication in orthopedic surgery. The use of antibiotic prophylaxis (AP) combined with other prevention strategies has been shown to reduce this risk to 1% for hip arthroplasty and 2% for knee arthroplasty. The French Society of Anesthesia and Intensive Care Medicine (SFAR) recommends doubling the dose when the patient's weight is greater than or equal to 100 kg, and the body mass index (BMI) is greater than or equal to 35 kg/m2. Similarly, patients with a BMIgreater than40 kg/m2 orlesser than18 kg/m2 are ineligible for surgery in our hospital. Self-reported anthropometric measurements are commonly used in clinical practice to calculate BMI, but their validity has not been assessed in the orthopedic literature. Therefore, we conducted a study comparing self-reported with systematically measured values and observed the impact these differences may have on perioperative AP regimens and contra-indications to surgery.

HYPOTHESIS

The hypothesis of our study was that self-reported anthropometric values differed from those measured during preoperative orthopedic consultations.

MATERIALS AND METHODS

This single-center retrospective study with prospective data collection was conducted between October and November 2018. The patient-reported anthropometric data were first collected and then directly measured by an orthopedic nurse. Weight was measured with a precision of 500 g and height was measured with a precision of 1 cm.

RESULTS

A total of 370 patients (259 women and 111 men) with a median age of 67 years (17-90) were enrolled. The data analysis found significant differences between the self-reported and measured height [166 cm (147-191) vs. 164 cm (141-191) (p<0.0001)], weight [72.9 kg (38-149) vs. 73.1 kg (36-140) (p<0.0005)] and BMI [26.3 (16.2-46.4) vs. 27 (16-48.2) (p<0.0001)]. Of these patients, 119 (32%) reported an accurate height, 137 (37%) an accurate weight, and 54 (15%) an accurate BMI. None of the patients had two accurate measurements. The maximum underestimation was 18 kg for weight, 9 cm for height, and 6.15 kg/m2 for BMI. The maximum overestimation was 28 kg for weight, 10 cm for height, and 7.2 kg/m2 for BMI. The verification of the anthropometric measurements identified another 17 patients who had contra-indications to surgery (12 with a BMI>40 kg/m2 and 5 with a BMI<18 kg/m2) and who would not have been detected based on the self-reported values.

CONCLUSIONS

Although patients underestimated their weight and overestimated their height in our study, these had no impact on the perioperative AP regimens. However, this misreporting failed to detect potential contraindications to surgery.

LEVEL OF EVIDENCE

IV; retrospective study with prospective data collection and no control group.

Prognostic Factors for Postoperative Chronic Pain after Knee or Hip Replacement in Patients with Knee or Hip Osteoarthritis: An Umbrella Review

Knee and hip osteoarthritis are highly prevalent in the older population. Management of osteoarthritis-related pain includes conservative or surgical treatment. Although knee or hip joint replacement is associated with positive outcomes, up to 30% of patients report postoperative pain in the first two years. This study aimed to synthesize current evidence on prognostic factors for predicting postoperative pain after knee or hip replacement. An umbrella review of systematic reviews was conducted to summarize the magnitude and quality of the evidence for prognostic preoperative factors predictive of postoperative chronic pain (>6 months after surgery) in patients who had received knee or hip replacement. Searches were conducted in MEDLINE, CINAHL, PubMed, PEDro, SCOPUS, Cochrane Library, and Web of Science databases from inception up to 5 August 2022 for reviews published in the English language. A narrative synthesis, a risk of bias assessment, and an evaluation of the evidence confidence were performed. Eighteen reviews (nine on knee surgery, four on hip replacement, and seven on both hip/knee replacement) were included. From 44 potential preoperative prognostic factors, just 20 were judged as having high or moderate confidence for robust findings. Race, opioid use, preoperative function, neuropathic pain symptoms, pain catastrophizing, anxiety, other pain sites, fear of movement, social support, preoperative pain, mental health, coping strategies, central sensitization-associated symptoms, and depression had high/moderate confidence for an association with postoperative chronic pain. Some comorbidities such as heart disease, stroke, lung disease, nervous system disorders, and poor circulation had high/moderate confidence for no association with postoperative chronic pain. This review has identified multiple preoperative factors (i.e., sociodemographic, clinical, psychological, cognitive) associated with postoperative chronic pain after knee or hip replacement. These factors may be used for identifying individuals at a risk of developing postoperative chronic pain. Further research can investigate the impact of using such prognostic data on treatment decisions and patient outcomes.

Activity Following Total Hip Arthroplasty: Which Patients Are Active, and Is Being Active Safe?

BACKGROUND

Younger and physically active patients demand a return to sport after total hip arthroplasty (THA). However, because of the risk of implant wear and loosening, high-impact activities are often not recommended. The current study evaluates predictive factors and revision rates in patients with higher activity levels.

METHODS

This retrospective study included 4152 hips in 3828 patients aged 45-75 that underwent primary THA for primary osteoarthritis between 2009 and 2019 with a minimum follow-up of 2 years. Pain and Lower Extremity Activity Scale (LEAS) were assessed before and 2 years after surgery. Activity was classified as low (LEAS 1-6), moderate (LEAS 7-13), or high (LEAS 14-18).

RESULTS

Pain and LEAS improved from preoperative to 2-years postoperative (p < 0.001). The activity level was low in 6.2%, moderate in 52.9%, and high in 40.9% of the patients. Younger age, lower BMI, ASA, and CCI, male sex, and higher preoperative LEAS correlated with higher activity at 2 years (p < 0.001). The predicted revision-free survival rates between the activity groups were better for more highly active patients (p < 0.001).

CONCLUSIONS

High physical activity 2 years following THA, with participating in sports like jogging several times a week, did not increase the risk of revision surgery. THA patients should not be prevented from a highly active lifestyle.

Go Big or Go Home: Obesity and Total Joint Arthroplasty

Obesity is highly prevalent, and it is expected to grow considerably in the United States. The association between obesity and an increased risk of complications following total joint arthroplasty (TJA) is widely accepted. Many believe that patients with body mass index (BMI) >40 have complications rates that may outweigh the benefits of surgery and should consider delaying it. However, the current literature on obesity and outcomes following TJA is observational, very heterogeneous, and full of confounding variables. BMI in isolation has several flaws and recent literature suggests shifting from an exclusively BMI <40 cutoff to considering 5 to 10% preoperative weight loss. BMI cutoffs to TJA may also restrict access to care to our most vulnerable, marginalized populations. Moreover, only roughly 20% of patients instructed to lose weight for surgery are successful and the practice of demanding mandatory weight loss needs to be reconsidered until convincing evidence exists that supports risk reduction as a result of preoperative weight loss. Obese patients can benefit greatly from this life-changing procedure. When addressing the potential difficulties and by optimizing preoperative assessment and intraoperative management, the surgery can be conducted safely. A multidisciplinary patient-centered approach with patient engagement, shared decision-making, and informed consent is recommended.

Free Hip Arthroplasty Templating Software - Does it Work?

Background

Preoperative planning is important for successful total hip arthroplasty (THA) and has been historically performed using acetate templates. Digital software templating has been adopted for evaluating implant size, position, and alignment. Commercial software can be expensive, but free programs exist. Detroit Bone Setter (detroitbonesetter.com, Detroit, MI) is a freely available templating program, but hasn't been validated. Our study reports this program's accuracy for templating THA.

Methods

Sixty-five patients undergoing THA between 2017 and 2022 at 2 hospitals were included. All cases were templated by the senior author or orthopaedic trauma fellow prospectively or retrospectively in a blinded fashion. Direct anterior or posterior approaches were used based on attending surgeon's preference. A student's t-test was used to compare means of templated vs actual implant sizes of femoral and acetabular components.

Results

There was no significant difference between implanted (mean [M] = 6.4, standard deviation [SD] = 2.0) and templated femoral component sizes (M = 5.7, SD = 2.1). There was a significant difference between implanted (M = 57.0, SD = 3.9) and templated acetabular component sizes (M = 53.4, SD = 3.0). Bland-Altman testing demonstrated femoral components with positive measurement bias of 0.62, indicating slight overestimation of implant size. Acetabular component size was overestimated with positive measurement bias of 3.6 mm.

Conclusions

Detroit Bone Setter is advantageous as it is freely available and supports most major company implants. It accurately templated femoral component size but consistently overestimated acetabular component size by 3.6 mm. Further studies are needed prior to recommending its routine use for templating THA when other validated methods exist. It could be used with caution when no other methods are available.

Visceral Fat as a Risk Factor for Periprosthetic Joint Infection After Total Hip and Knee Arthroplasty

BACKGROUND

Visceral obesity, a strong indicator of chronic inflammation and impaired metabolic health, has been shown to be associated with poor postoperative outcomes and complications. This study aimed to evaluate the relationship between visceral fat area (VFA) and periprosthetic joint infection (PJI) in total joint arthroplasty (TJA) patients.

METHODS

A retrospective study of 484 patients who had undergone a total hip or knee arthroplasty was performed. All patients had a computed tomography scan of the abdomen/pelvis within two years of their TJA. Body composition data (ie, VFA, subcutaneous fat area, and skeletal muscle area) were calculated at the Lumbar-3 vertebral level via two fully automated and externally validated machine learning algorithms. A multivariable logistic model was created to determine the relationship between VFA and PJI, while accounting for other PJI risk factors. Of the 484 patients, 31 (6.4%) had a PJI complication.

RESULTS

The rate of PJI among patients with VFA in the top quartile (> 264.1 cm2) versus bottom quartile (< 82.6 cm2) was 5.6% versus 10.6% and 18.8% versus 2.7% in the total hip arthroplasty and total knee arthroplasty cohorts, respectively. In the multivariate model, total knee arthroplasty patients with a VFA in the top quartile had a 30.5 times greater risk of PJI than those in the bottom quartile of VFA (P = .0154).

CONCLUSION

VFA may have a strong association with PJI in TJA patients. Using a standardized imaging modality like computed tomography scans to calculate VFA can be a valuable tool for surgeons when assessing risk of PJI.

Catastrophic Early Failure and Fragmentation of a Modern Moderately Cross-linked Polyethylene Acetabular Liner

A 60-year-old man who underwent uncomplicated staged bilateral total hip arthroplasty for femoral head osteonecrosis presented with mechanical catching of his left total hip arthroplasty 3 years after index surgery. Radiographs revealed eccentricity of the left femoral head, concerning the failure of a modern moderately cross-linked polyethylene liner. Catastrophic polyethylene liner failure with significant wear, fragmentation, and femoral head abrasion was noted during revision surgery. The original liner and head were replaced, and the patient has exhibited no complications, pain, or difficulty ambulating 6 months postoperatively. This report highlights one potential novel mechanism for the failure of the Exactech Connexion GXL liner (Exactech Inc., Gainesville, FL), an implant recently reported to have a higher-than-expected failure rate, potentially due to insufficient packaging and increased oxidative processes.

Total Ankle Arthroplasty: Does Obesity Matter?

BACKGROUND

There is limited data evaluating the effect of obesity on outcomes following total ankle arthroplasty (TAA), especially in adequate sample sizes to detect impacts on patient-reported outcomes (PROs). The purpose of this study was to assess the effect of obesity on complication rates and PROs.

METHODS

This was a single-institution, retrospective study of 1093 primary TAA performed between 2001 and 2020. Minimum follow-up was 2 years. Patients were stratified by body mass index (BMI) into control (BMI = 18.5-29.9; n = 615), obesity class I (BMI = 30.0-34.9; n = 285), and obesity class II (BMI > 35.0; n = 193) groups. Patient information, intraoperative variables, postoperative complications, and PRO measures were compared between groups using univariable statistics. Multivariable Cox regression was performed to assess risk for implant failure. Mean follow-up was 5.6 years (SD: 3.1).

RESULTS

Compared to control and class I, class II patients had the lowest mean age (P = .001), highest mean ASA score (P < .001), and greatest proportion of female sex (P < .001) and Black/African American race (P = .005). There were no statistically significant differences in postoperative complications (infection, implant failure, or impingement) across the BMI classes (P > .05).Preoperatively, class II had lower (worse) mean scores for Foot and Ankle Outcome Score pain and ADL subscales than controls (post hoc pairwise P < .001 for both). At final follow-up, both class II and class I had lower (worse) mean Short Musculoskeletal Function Assessment (post hoc pairwise P < .001 and P = .030, respectively) and 36-Item Short Form Health Survey scores (post hoc pairwise P < .001 and P = .005, respectively) than controls.

CONCLUSION

At midterm follow-up, obesity was not associated with increased rates of complications after TAA. Patients with obesity reported worse musculoskeletal function and overall quality of life after TAA but there was no differential improvement in PROs across BMI classes. To our knowledge, this is the largest single-institution study to date examining the effect of obesity on outcomes after primary TAA.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Obesity is associated with an increased risk of undergoing hip replacement in Australia

BACKGROUND

Obesity is a known risk factor for the development of hip osteoarthritis. The aim of this study was to investigate whether obesity is associated with the risk of undergoing total hip replacement (THR) in Australia.

METHODS

A cohort study was conducted comparing data from the Australian Bureau of Statistics and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 2017 to 2018. Body mass index (BMI) data for patients undergoing primary total hip replacement and resurfacing for osteoarthritis were obtained from the AOANJRR. The distribution of THR patients by BMI category was compared to the general population, in age and sex sub-groups.

RESULTS

During the study period, 32 495 primary THR were performed for osteoarthritis in Australia. Compared to the general population, there was a higher prevalence of Class I, II and III obesity in patients undergoing THR in both sexes aged 35-74 years. Class III obese females and males aged 55-64 years were 2.9 and 1.7 times more likely to undergo THR, respectively (P < 0.001). Class III obese females and males underwent THR on average 5.7 and 7.0 years younger than their normal weight counterparts, respectively.

CONCLUSION

Obese Australians are at increased risk of undergoing THR, and at a younger age.

Outcomes of morbidly obese patients undergoing total hip arthroplasty with the anterior-based muscle-sparing approach

Obesity is associated with an increased risk of hip osteoarthritis, resulting in an increased number of total hip arthroplasties (THAs) performed annually. This study examines the peri- and postoperative outcomes of morbidly obese (MO) patients (BMI ≥ 40 kg/m²) compared to healthy weight (HW) patients (BMI 18.5 to < 25 kg/m²) who underwent a THA using the anterior-based muscle-sparing (ABMS) approach. This retrospective cohort study observes peri- and postoperative outcomes of MO and HW patients who underwent a primary, unilateral THA with the ABMS approach. Data from surgeries performed by three surgeons at a single institution was collected from January 2013 to August 2020 and analyzed using Microsoft Excel and Stata 17.0. This study compares 341 MO to 1,140 HW patients. Anaesthesia, surgery duration, and length of hospital stay was significantly lower in HW patients compared to MO. There was no difference in incidence of pulmonary embolism, periprosthetic fracture, or dislocation between the two groups. The rate of infection in MO patients (1.47%) was significantly higher than HW patients (0.14%). Preoperative patient-reported outcome measures (PROMs) show a significantly higher pain level in MO patients and a significantly lower score in functional abilities. Overall, six-week and one-year postoperative data show higher levels of pain, lower levels of functional improvement, and lower satisfaction scores in the MO group. The comorbidities of obesity are well studied; however, the implications of THA using the ABMS approach have not been studied. Our peri- and postoperative results demonstrate significant improvements in PROMs in MO patients undergoing THA. However, the incidence of deep infection was significantly higher in this group compared with HW patients.

Fracture of Contemporary Femoral Stems: Common Trends in This Rare Occurrence

BACKGROUND

Fracture of contemporary femoral stems is a rare occurrence in total hip arthroplasty (THA). A knowledge gap remains regarding manufacturing, patient, and surgeon factors that may contribute to the increased risk of this complication.

METHODS

We analyzed 13 contemporary fractured porous coated femoral stems of various designs to determine cause and contributing factors of mechanical failure. Cases included 12 men and one woman who had an average age at index surgery of 53 years (range, 34 to 76). There were ten of 13 patients who had a body mass index (BMI) greater than 30 (obese); 3 of the 10 had a BMI greater than 40. The mean time to fracture was 7.6 years (range, 7 months to 12 years).

RESULTS

There were four titanium alloy stems that fractured an average of 3.6 years post-revision surgery for head/cup exchange, and had associated iatrogenic mechanical and electrocautery damage to the femoral neck at fracture initiation sites. There were six modular stems that failed at the stem-sleeve or stem-neck interfaces with evidence of fretting corrosion. For two stem-neck fractures, mis-matched head/stem combinations from different manufacturers resulted in untested mechanical offsets and loading. There were two proximal neck fractures and one mid-shaft fracture of coated cobalt-chromium alloy stems that occurred in three obese men. The neck fractures (10 to 12 years) were well-fixed stems. Lack of proximal fixation contributed to the mid-shaft fracture (7 months).

CONCLUSION

While rare, femoral stem fractures pose catastrophic outcomes in primary and revision THA. Manufacturing, patient, and surgical factors contributing to stem failures were identified, including patient obesity, heat-treatment reduction of mechanical properties, iatrogenic implant damage, and mixing of different vendor stems and heads.

Is the Direct Anterior Approach for Total Hip Arthroplasty Effective in Obese Patients? Early Clinical and Radiographic Results from a Retrospective Comparative Study

Background and objectives: Total hip arthroplasty (THA) in obese patients (BMI > 30) is considered technically demanding, and it is associated with higher rates of general and specific complications including infections, component malpositioning, dislocation, and periprosthetic fractures. Classically, the Direct Anterior Approach (DAA) has been considered less suitable for performing THA surgery in the obese patient, but recent evidence produced by high-volume DAA THA surgeons suggests that DAA is suitable and effective in obese patients. At the authors' institution, DAA is currently the preferred approach for primary and revision THA surgery, accounting for over 90% of hip surgeries without specific patient selection. Therefore, the aim of the current study is to evaluate any difference in early clinical outcomes, perioperative complications, and implant positioning after primary THAs performed via DAA in patients who were divided according to BMI. Material and methods: This study is a retrospective review of 293 THA implants in 277 patients that were performed via DAA from 1 January 2016 to 20 May 2020. Patients were further divided according to BMI: 96 patients were normal weight (NW), 115 were overweight (OW), and 82 were obese (OB). All the procedures were performed by three expert surgeons. The mean follow-up was 6 months. Patients' data, American Society of Anesthesiologists (ASA) score, surgical time, days in rehab unit, pain at the second post-operative day recorded by using a Numerical Rating Scale (NRS), and number of blood transfusions were recorded from clinical charts and compared. Radiological evaluation of cup inclination and stem alignment was conducted on post-operative radiographs; intra- and post-operative complications at latest follow-up were recorded. Results: The average age at surgery of OB patients was significantly lower compared to NW and OW patients. The ASA score was significantly higher in OB patients compared to NW patients. Surgical time was slightly but significantly higher in OB patients (85 ± 21 min) compared to NW (79 ± 20 min, p = 0.05) and OW patients (79 ± 20 min, p = 0.029). Rehab unit discharge occurred significantly later for OB patients, averaging 8 ± 2 days compared to NW patients (7 ± 2 days, p = 0.012) and OW patients (7 ± 2 days; p = 0.032). No differences in the rate of early infections, number of blood transfusions, NRS pain at the second post-operative day, and day of post-operative stair climbing were found among the three groups. Acetabular cup inclination and stem alignment were similar among the three groups. The perioperative complication rate was 2.3%; that is, perioperative complication occurred in 7 out of 293 patients, with a significantly higher incidence of surgical revisions required in obese patients compared to the others. In fact, OB patients showed a higher revision rate (4.87%) compared to other groups, with 1.04% for NW and 0% for OW (p = 0.028, Chi-square test). Causes for revision in obese patients were aseptic loosening (2), dislocation (1), and clinically significant post-operative leg length discrepancy (1), with a revision rate of 4/82 (4.87%) during follow-up. Conclusions: THA performed via DAA in obese patients could be a solid choice of treatment, given the relatively low rate of complications and the satisfying clinical outcomes. However, surgical expertise on DAA and adequate instrumentation for this approach are required to optimise the outcomes.

A Reduction in Body Mass Index From ≥ 40 to < 40 Lowers Emergency Department Visits, but May Increase All-Cause Readmissions After Primary Total Hip Arthroplasty: Conflicting 90-Day Outcomes at a Single Institution

BACKGROUND

The American Association of Hip and Knee Surgeons tasked a 2013 workgroup to provide obesity-related recommendations in total joint arthroplasty. Morbidly obese patients (body mass index (BMI) ≥ 40) seeking hip arthroplasty were determined to be at increased perioperative risk, and surgeons were recommended to encourage these patients to reduce their BMI <40 presurgery. We report the effect of instituting a 2014 BMI <40 threshold on our primary total hip arthroplasties (THAs).

METHODS

We queried our institutional database to select all primary THAs from January 2010 to May 2020. There were 1,383 THAs that were pre-2014 and 3,273 THAs that were post-2014. The 90-day emergency department (ED) visits, readmissions, and returns to operating room (OR) were identified. Patients were propensity score weight-matched according to comorbidities, age, initial surgical consultation (consult) BMI, and sex. We conducted 3 comparisons: A) pre-2014 patients who had a consult and surgical BMI ≥40 against post-2014 patients who had a consult BMI ≥40 and surgical BMI <40; B) pre-2014 patients against post-2014 patients who had a consult and surgical BMI <40; and C) post-2014 patients who had a consult BMI ≥40 and surgical BMI <40 against post-2014 patients who had a consult BMI ≥40 and surgical BMI ≥40.

RESULTS

Post-2014 patients who had a consult BMI ≥ 40 and surgical BMI <40 had less ED visits (7.6 versus 14.1%, P = .0007), but similar readmissions (11.9 versus 6.3%, P = .22) and returns to OR (5.4 versus 1.6%, P = .09) compared to pre-2014 patients who had a consult BMI and surgical BMI ≥ 40. Post-2014 BMI <40 had less readmissions (5.9 versus 9.3%, P < .0001), and similar all-cause returns to OR and ED visits than patients pre-2014. Post-2014 patients who had a consult and surgical BMI ≥ 40 had lower readmissions (12.5 versus 12.8%, P = .05), and similar ED visits and returns to OR than consult BMI ≥ 40 and surgical BMI <40.

CONCLUSION

Patient optimization prior to total joint arthroplasty is critical. However, the BMI optimization that mitigates risk in primary total knee arthroplasty may not apply to primary THA. We observed a paradoxical increased readmission rate for patients who reduced their BMI before THA.

LEVEL OF EVIDENCE

III.

Dual-Mobility Cups in Primary Total Hip Arthroplasty

Dual-mobility cups (DMCs) were introduced in France more than 40 years ago and are increasingly used not only in hip revision but also primary hip arthroplasty. Due to a simulated large-head articulation and increased jumping distance, DMCs can contribute to a high range of motion in the hip joint and reduce the risk of instability. Numerous studies have reported low dislocation rates and high survival rates in the mid-term follow-up. Nevertheless, long-term data, especially on primary hip replacement, remain limited, and the effect of recent designs and material innovations is still unclear. Therefore, primary DMCs are mainly proposed in patients at high risk for dislocation (i.e. pelvitrochanteric insufficiency, compromised spinopelvic mobility, neuromuscular disorders, obesity and femoral neck fractures). Based on a review of recently published studies referring to these indications, the current study discusses the advantages and disadvantages of DMCs.

The Safety and Efficacy of the Anterior Approach Total Hip Arthroplasty as per Body Mass Index

BACKGROUND

Obesity is associated with component malpositioning and increased revision risk after total hip arthroplasty (THA). With anterior approaches (AAs) becoming increasingly popular, the goal of this study was to assess whether clinical outcome post-AA-THA is affected by body mass index (BMI).

METHODS

This multicenter, multisurgeon, consecutive case series used a prospective database of 1,784 AA-THAs (1,597 patients) through bikini (n = 1,172) or standard (n = 612) incisions. Mean age was 63 years (range, 20-94 years) and there were 57.5% women, who had a mean follow-up of 2.7 years (range, 2.0-4.1 years). Patients were classified into the following BMI groups: normal (BMI < 25.0; n = 572); overweight (BMI: 25.0-29.9; n = 739); obese (BMI: 30.0-34.9; n = 330); and severely obese (BMI ≥ 35.0; n = 143). Outcomes evaluated included hip reconstruction (inclination/anteversion and leg-length, complications, and revision rates) and patient-reported outcomes including Oxford Hip Scores (OHS).

RESULTS

Mean postoperative leg-length difference was 2.0 mm (range: -17.5 to 39.0) with a mean cup inclination of 34.8° (range, 14.0-58.0°) and anteversion of 20.3° (range, 8.0-38.6°). Radiographic measurements were similar between BMI groups (P = .1-.7). Complication and revision rates were 2.5% and 1.7%, respectively. The most common complications were fracture (0.7%), periprosthetic joint infection (PJI) (0.5%), and dislocation (0.5%). There was no difference in dislocation (P = .885) or fracture rates (P = .588) between BMI groups. There was a higher rate of wound complications (1.8%; P = .053) and PJIs (2.1%; P = .029) among obese and severely obese patients. Wound complications were less common among obese patients with the 'bikini' incision (odds ratio 2.7). Preoperative OHS was worse among the severely obese (P < .001), which showed similar improvements (Change in OHS; P = .144).

CONCLUSION

AA-THA is a credible option for obese patients, with low dislocation or fracture risk and excellent ability to reconstruct the hip, leading to comparable functional improvements among BMI groups. Obese patients have a higher risk of PJIs. Bikini incision for AA-THA can help minimize the risk of wound complications.

The Use of Continuous Positive Airway Pressure for Patients With Obstructive Sleep Apnea is Associated With Early Medical and Surgery-Related Complications Following Total Knee Arthroplasty: A National Database Study

Background

Obstructive sleep apnea (OSA) has been shown to increase the risk of complications following total knee arthroplasty (TKA) although prior studies were limited by their ability to stratify OSA patients by disease severity. The objective of this study was to determine the effect size of the use of continuous positive airway pressure (CPAP) on early medical and surgery-related complications following TKA among patients with OSA.

Methods

Patients with OSA who underwent primary TKA were identified using the PearlDiver Mariner database. Ninety-day incidences of medical complications and 1-year incidences of surgery-related complications as well as hospital utilization were evaluated for OSA patients who had used CPAP prior to TKA compared to those who did not.

Results

CPAP patients were at increased 90-day risk of emergency department presentation (odds ratio [OR] 1.61; P < .0001), hospital admission (OR 1.33; P < .001), ICU admission (OR 1.45, P < .0001), pulmonary embolism (OR 1.68, P < .0001), deep vein thrombosis (OR 1.31, P < .0001), transfusion (OR 1.89, P < .0001), pneumonia (OR 1.63, P < .0001), cerebrovascular accident (OR 1.92, P < .0001), myocardial infarction (OR 1.57, P = .0015), sepsis (OR 1.35, P = .0025), blood loss anemia (OR 1.67, P < .0001), acute kidney injury (OR 1.65, P < .0001), and urinary tract infection (OR 1.99, P < .0001), as well as increased 1-year risk of undergoing revision surgery (OR 1.14, P = .0028), compared to OSA patients not using CPAP.

Conclusions

OSA patients on CPAP undergoing TKA have significantly increased complication rates compared to OSA patients not using CPAP.

Level of Evidence

III, Retrospective review.

Outcomes of the overweight and obese major trauma patient in the rural setting

PURPOSE

Overweight and obese patients are more prevalent in rural and remote areas and are of major public health concern in Australia. We aimed to evaluate the mortality and morbidity of overweight and obese trauma patients in the rural Australian context.

METHOD

This was a retrospective cohort study on 207 major trauma patients (injury severity score [ISS] > 12) treated at the Mackay Base Hospital between 2018 and 2021. Data was extracted from the Mackay Base Hospital trauma database and hospital records. Outcomes were compared between body mass index (BMI) groups.

RESULTS

There were 164 males (79%) and 43 females (21%). The average BMI was 27.09 (standard deviation 5.46). 7 patients (3%) were in the underweight category (BMI < 18.5 kg/m²), 70 (34%) were of normal weight (BMI 18.5-24.9 kg/m²), 79 (38%) were overweight (BMI 25-29.9 kg/m²), and 51 (25%) were obese (BMI > 30 kg/m²). The majority of trauma was blunt (n = 203, 98%). Compared to patients with normal BMI, obese patients were significantly more likely to require intubation, intensive care unit (ICU) admission, and have a longer ICU stay. There were no significant differences in requirement for surgery, duration of surgery, hospital length of stay, ventilator time, or mortality (P > 0.05). However, subgroup analysis of the obese patient group showed an increased rate of complications (sepsis, acute kidney injury, fluid overload and pneumonia), longer ventilation times, hospital and ICU length of stay with increasing BMI in these patients.

CONCLUSION

The majority of trauma presentations in our regional community are in overweight or obese patients. Overweight and obese patients are more likely to require intubation and have a longer intensive care unit admission than normal weight counterparts. Amongst obese patients, those with BMI > 40 (obesity class 3) are at significantly increased risk of complications.

Mechanical failure of total hip arthroplasties and associated risk factors

INTRODUCTION

Mechanical failure of total hip arthroplasties is a rare but devastating complication. With increasing numbers in primary arthroplasty implantation, revision surgeries are indicated more often. Therefore, understanding the mechanism and the location of failure is essential in determining proper treatment. Aim of this study was to identify mechanical failures of all total hip arthroplasties performed in a major academic center as well as the associated risk factors such as BMI and sports.

METHODS

A retrospective trial was conducted using our prospective arthroplasty database. Database was searched for all patients presenting with mechanical failures of total hip arthroplasty (THA) to the emergency department between 2011 and 2019. All medical charts and radiographs as well as surgical reports were analyzed to identify demographics, implant choice in addition to location of failure and subsequent treatment.

RESULTS

In total, 13 patients suffering from mechanical total hip implant failure were found. The femoral neck (conus) was broken in four patients, the stem in five cases, one broken inlay, two cup failures and one conus dislocation. The mean BMI was 31.42 ± 5.29 kg/m² including five patients who have obesity class II. In all cases, revision surgeries were indicated. No structural causes or underlying risk factors such as repeated physical load (i.e. in sports) were identified.

CONCLUSION

Implant failure does not seem to correlate with participation in sports or BMI. Catastrophic failure of implants is a technical challenge requiring special extraction instruments that can be difficult even for experienced surgeons. It should be noted that functional outcome is often worse for this group of patients after surgery than comparing against those revised for loosening.

LEVEL OF EVIDENCE

III, Retrospective Trial.

Patients of Obese Representation Require Longer Operative Times: An Evaluation of Acetabular and Pelvic Ring Operative Duration

Recent literature has determined that operative times for the obese population are greater for both elective and nonelective orthopedic procedures. If time allotted for a given surgical procedure is used as a measure of procedural difficulty, then consideration can be given for using an additional coding modifier (i.e., Modifier 22) for the increased skill and effort associated with longer procedures. A retrospective chart review was conducted on all patients who underwent surgical treatment for an acute fracture about the pelvis at an urban level-1 trauma center from October 1, 2010 through October 31, 2018. After allowing for both inclusion and exclusion criteria, 102 patients with acetabular fractures and 55 patients with pelvic ring injuries were included in this investigation. The obese population within the acetabular fracture cohort demonstrated significantly longer mean times for the duration of surgery, total time in spent in the operating room, and duration under anesthesia (P values of 0.038, 0.05 and 0.035, respectively). Similar results were observed with the pelvic ring injury cohort, with significantly longer procedural times (P = 0.019), total time in the operating room (P = 0.034), and total duration under anesthesia (P = 0.0395). A trend towards a greater risk of infection was found in obese patients (7%) when compared with nonobese patients (1.6%) within the acetabular fracture subset (P = 0.093). Operative duration for acetabular fractures and pelvic ring injuries is significantly longer in the obese population. Furthermore, this indicates that a Modifier 22 may be justified for the surgical treatment of these injuries in the obese and morbidly obese patient populations.

Obesity and total joint arthroplasty: Does weight loss in the preoperative period improve perioperative outcomes?

Background

The obese population is more likely to develop degenerative joint disease requiring total joint arthroplasty (TJA) and also experience increased rates of adverse post-surgical outcomes. This study assessed whether a quantifiable weight loss prior to TJA had any impact on perioperative and 30-day outcomes in obese patients.

Method

Using the American College of Surgeons-National Surgical Quality Improvement Program database, obese patients who underwent total hip or total knee arthroplasty and lost at least 10% of their total body weight prior to surgery were identified and matched to other obese individuals undergoing the same procedures without weight loss. Perioperative outcomes, including operative time, length of stay, discharge destination, or 30-day adverse events, including complications, re-admissions, re-operations, and mortality, were then compared using conditional Logistic regression analysis.

Results

Analysis showed no difference between the two groups in terms of operative time, length of stay, discharge destination, or 30-day adverse events, including complications, re-admissions, re-operations, and mortality.

Conclusion

The results of this study suggest that weight loss alone in the preoperative period may not be sufficient to mitigate the effects of obesity on immediate post-TJA outcomes.

Elective hip arthroplasty rates and related complications in people with diabetes mellitus

BACKGROUND AND AIMS

Diabetes mellitus (DM), poor glycaemic control and raised body mass index (BMI) have been associated with postoperative complications in arthroplasty, although the relative importance of these factors is unclear. We describe the prevalence of DM in elective hip arthroplasty in a UK centre, and evaluate the impact of these factors.

METHODS

We analysed retrospective data for DM patients undergoing arthroplasty over a 6-year period and compared with non-diabetic matched controls (1 DM patient: 5 controls). DM was present in 5.7% of hip arthroplasty patients (82/1443).

RESULTS

Postoperative complications occurred in 12.2% of DM patients versus 12.9% of controls (p = 1.000); surgical complications were present in 6.1% of those with DM and 2.4% of controls (p = 0.087), while medical complications occurred in 8.5% of DM patients versus 10.7% of controls (p = 0.692). Complications developed in 23.1% of DM patients with poor glycaemic control (HbA1c > 53 mmol/mol) versus 9.8% with good control (p = 0.169). In DM patients and controls combined, complications occurred in 16.3% of obese patients versus 10.0% of non-obese patients (p = 0.043). In the DM cohort, 13.7% of overweight patients had complications versus 0% with a normal or low BMI (p = 0.587).

CONCLUSIONS

DM rates were lower than expected, and glycaemic control was good. Overall complication rates were unrelated to the presence of DM or to glycaemic control, although surgical complications were observed more frequently in those with DM and poor glycaemic control was uncommon within our cohort. Complications were more frequent in those with a higher BMI. Whether some patients with DM but without an increased risk of complications are currently being excluded from surgery requires exploration.

The effect of obesity on complications following isolated posterior cruciate ligament reconstruction

BACKGROUND

This study assessed the risk of 30-day complications for obese patients compared to non-obese patients undergoing isolated posterior cruciate ligament (PCL) reconstruction.

METHODS

From 2006 to 2019, the National Surgical Quality Improvement Program database was queried for patients undergoing isolated PCL reconstruction. Two patient cohorts were defined: patients with obesity (BMI ≥ 30.0 kg/m²) and patients without obesity (BMI < 30 kg/m²). Patients' baseline demographics and medical comorbidities were collected and compared between the cohorts. Postoperative outcomes were assessed using bivariate and multivariate analyses.

RESULTS

414 patients underwent PCL reconstruction. 258 patients (62.3%) were non-obese and 156 patients (37.7%) were obese. Obese patients were more likely to be older, have a higher American Society of Anesthesiologists classification, and have hypertension compared to non-obese patients (p < 0.05 for all). The rates of superficial surgical site infections, wound dehiscence, transfusion necessity, deep vein thrombosis, and re-operation were not significant between obese and non-obese patients. Following adjustment on multivariate analyses, relative to patients without obesity, those with obesity had an increased risk of admission to the hospital overnight (OR 1.66; p = 0.048).

CONCLUSIONS

To our knowledge, this is the first study to evaluate obesity on complications in isolated PCL reconstruction. Our results and the heterogeneity in the literature indicate that obesity significantly impacts the rates of hospital readmission for PCL reconstruction. Therefore, surgeons should carefully weigh the risks and benefits of operating on obese patients and plan accordingly as obese patients may require postoperative hospital admission after PCL reconstruction.

LEVEL OF EVIDENCE

III.

Trends of obesity rates between primary total hip arthroplasty patients and the general population from 2013 to 2020

Background

The prevalence of obesity in total hip arthroplasty (THA) patients has been studied in the past. However, there has not been direct comparison against obesity in the general population. This study compared yearly trends in BMI and obesity rates between patients who had undergone primary THA and those from the general patient population.

Methods

We retrospectively reviewed all patients over the age of 18 who underwent primary, elective THA and those who had an annual routine physical exam between January 2013 and December 2020 at our academic tertiary medical center. Baseline demographics were controlled in our statistical models. Significance of yearly trends was determined through a linear regression analysis. Independent samples t-test and Chi-square test were used to compare means and proportions between the two groups, respectively.

Results

A total of 11,250 primary THA patients and 1,039,918 annual physical exam patients were included. Average BMI for the THA group was significantly higher (P < 0.001) each year compared to the annual physicals group (APG). Higher obesity rates were observed in all obesity subgroups (all classes, and class I–III individually) for THA patients each year compared to the APG. Interestingly, while we found a significantly increasing trend in obesity for the general population (P < 0.001), BMI and obesity rates remained stable in the THA population.

Conclusion

While our general patient population showed significant increase in BMI and obesity over time, THA patients had higher, yet stable, BMI. Further investigation is required to determine the role of risk optimization in these findings.

Level III Evidence

Retrospective Cohort Study.

The accuracy of patient-reported weight prior to total joint arthroplasty and arthroscopy of the lower extremity

PURPOSE

The accuracy of preoperative patient-reported weight was never evaluated in patients undergoing lower extremity procedures. The purpose of this study was to: (1) compare the disparity between patient-reported and measured weights in patients undergoing lower extremity total joint arthroplasty (LE-TJA) and arthroscopy; and (2) investigate the association between patient-specific factors (patient age, BMI, zip code, and psychiatric comorbidities) and the accuracy of patient-reported weight.

METHODS

Preoperative self-reported weights were retrospectively compared to measured weights in 400 LE-TJA and 85 control arthroscopy patients. The difference between reported and measured weights was calculated. Additionally, the percent of accurate reporting within 0.5, 1, and 5 kg ranges of the measured weight was calculated. Outcomes were compared between surgical modalities as well as between patient-specific factors.

RESULTS

There was low disparity (p = 0.838) between patient-reported and measured weights among LE-TJA (mean difference 0.18 ± 3.63 kg; p = 0.446) and that of arthroscopy (0.27 ± 4.08 kg; p = 0.129) patients. Additionally, LE-TJA patients were equally likely to report weights accurately within 0.5 kg of the measured weight (74% vs. 71.76%; p = 0.908). LE-TJA and arthroscopy patients had similar reporting accuracy within 1 and 5 kg of the measured weights (p > 0.05).

CONCLUSION

Preoperative patient-reported weights demonstrated acceptable accuracy in both LE-TJA and lower extremity arthroscopic orthopaedic patient populations making it a potentially reliable parameter of preoperative assessment.

Does obesity lead to lower rates of clinically meaningful improvement or satisfaction after total hip arthroplasty? A propensity score-matched study

BACKGROUND

Current literature lacks consensus regarding the impact of obesity on clinical outcomes of total hip arthroplasty (THA). The variability of results may reflect the lack of minimal clinically important difference (MCID) analysis, which helps to standardise the interpretation of patient-reported outcome measures (PROMs). We compared the PROMs, patient satisfaction and survivorship between obese and non-obese patients after THA.

METHODS

Prospectively collected registry data of 192 obese patients and 192 propensity score-matched controls who underwent primary THA at a single institution were reviewed. Clinical outcomes and satisfaction rates were assessed at 6 months and 2 years. Reoperations for surgical complications and revision rates were analysed.

RESULTS

Obese patients had a significantly poorer Oxford Hip Score (OHS) at 6 months and WOMAC-Function at 2 years. However, there was no difference in overall WOMAC, WOMAC-Pain, WOMAC-stiffness, SF-36 mental and physical component summary (PCS). A similar proportion of patients in each group achieved the MCID for OHS, WOMAC and SF-36 PCS. At 2 years, 90.3% of obese patients and 91.7% of controls were satisfied (p = 0.755). At a mean follow-up of 9 years, there were 5 reoperations (2.6%) for surgical complications in the obese group and 1 (0.5%) in the control group; whereas 12 revisions (6.3%) were recorded in the obese group and 3 (1.6%) in the control group (p = 0.021).

CONCLUSIONS

Despite a higher revision rate, obese patients undergoing THA may experience a similar level of clinical meaningful improvement and satisfaction as their non-obese counterparts. This study provides valuable prognostic information for obese patients and guides preoperative counselling.

The Impact of Morbid Obesity on In-hospital Outcomes after Revision Total Hip Arthroplasty: An Analysis of the National Inpatient Sample

Introduction:

There remain limited data on the effect of obesity on in-hospital outcomes after revision total hip arthroplasty (rTHA).

Methods:

Discharge data from the National Inpatient Sample were used to identify patients undergoing rTHA from 2006 to 2015. Propensity score analysis was done to analyze the effects of obesity and morbid obesity on in-hospital economic and complication outcomes after rTHA.

Results:

The estimated 460,297 rTHAs were done during the study period. Obese patients were more likely to suffer from any complication than not obese patients (41.44% versus 39.41%, P = 0.0085), and morbidly obese patients were more likely to suffer from any complication than obese patients (47.22% versus 41.44%, P < 0.0001). Obesity was associated with increased risk of postoperative anemia compared with not obese patients, while morbid obesity was associated with increased risk of postoperative anemia, hematoma/seroma, wound dehiscence, and postoperative infection (P < 0.05). Morbidly obese patients also had a significantly greater average length of stay (6.40 days) than obese (5.23 days) and not obese (5.37 days) patients (P < 0.0001).

Discussion:

Although both obesity and morbid obesity are associated with higher risk of in-hospital postoperative complications after rTHA, morbid obesity is a larger risk factor and is associated with a longer length of stay.

The Impact of Obesity on Total Hip Arthroplasty Outcomes: A Retrospective Matched Cohort Study

Aim

Previous research has shown that obesity is associated with worse postoperative outcomes. We aim to determine how rates of specific complications after total hip arthroplasty (THA) align with obesity status. We hypothesize that obese patients would have higher rates of complications and cost and thus have worse outcomes than non-obese patients.

Methods

Data were collected from a large commercial insurance database between 2011 and 2020. Patients underwent a hip replacement under current procedural terminology (CPT) and International Statistical Classification of Diseases (ICD-9/ICD-10) codes. Obese (defined as having a BMI of 30 kg/m² or higher) and non-obese patients were matched on age, gender, Charlson Comorbidity Index (CCI), and Elixhauser Comorbidity Index (ECI). Standardized complications and costs in one year were compared using unequal variance t-tests.

Results

Under CPT codes, 61,462 obese (45% male) and 61,462 non-obese patients (45% male) underwent a hip replacement. Obese patients had significantly higher rates of surgical site infection (SSI) (OR=1.193, p=0.0001), deep vein thrombosis (DVT) (OR=1.275, p=0.001), wound complication (OR=1.736, p<0.0001), hematoma (OR=1.242, p=0.0001), pulmonary embolism (OR=1.141, p=0.0355), UTI (OR=1.065, p=0.0016), and opioid prescriptions (OR=1.17, p<0.0001), and significantly lower rates of arrhythmia (OR=0.907, p<0.0001), congestive heart failure (CHF) (OR=0.863, p<0.0001), cardiac arrest (OR=0.637 p<0.0001), pneumonia (OR=0.795, p<0.0001), and transfusion (OR=0.777, p<0.0001). Furthermore, obese patients were significantly more likely to undergo revision within 10 years (OR=1.172, p<0.0001). Under ICD codes, 31,922 obese (45% male) and 31,922 non-obese patients (45% male) were included. Obese patients did not have a significant difference in total cost or drug cost.

Conclusions

Obese patients had significantly higher rates of infection, venous thromboembolic event, wound complication, hematoma, and opioid prescriptions but significantly lower rates of cardiac issues, pneumonia, and transfusion, after hip replacement. Additionally, there was no significant difference in total or drug cost. Therefore, this study did not support our hypothesis that obese patients have worse outcomes than non-obese patients, as there neither was a clear significant increase in complication rates nor a significant increase in costs. However, further research should be done to better understand the complex relationship between obesity and postoperative outcomes.

The effects of body mass index on insulin resistance in patients undergoing total hip arthroplasty: a pilot study

PURPOSE

We aimed to examine the effects of body mass index (BMI) on insulin resistance (IR), glycaemic control and adverse events in patients undergoing total hip arthroplasty (THA).

METHODS

A total of 118 patients undergoing THA were enrolled in this prospective cohort study and divided into two groups based on their BMI: Group A (n = 50, 18.5 ≤ BMI < 24 kg/m²) and Group B (n = 68, BMI ≥ 24 kg/m²). IR was calculated using Homeostasis Model Assessment 2 (HOMA2). Insulin resistance indicators, fasting plasma glucose (FPG), inflammatory markers, blood loss, length of stay and complications were compared between the two groups.

RESULTS

Multivariate analysis using generalized estimating equations revealed that BMI and surgery stress were risk factors for IR (P < 0.001). These two factors exhibited significant interactions for HOMA2-IR on post-operative day one (Exp (B) = 1.880, P = 0.003), accompanied by a higher level of FPG (Group B versus Group A, P = 0.004). Furthermore, subgroup analysis based on the IR value demonstrated that patients in Group B with a HOMA2-IR greater than 2.25 after surgery were at increased risk of wound complications (P = 0.045). Similarly, our results showed that the rate of post-operative hyperglycaemia was notably higher in Group B than in Group A (P = 0.013).

CONCLUSION

Patients with high BMI may experience significantly elevated IR and increased risk of hyperglycaemia and wound complications after THA. Therefore, routine glycaemia monitoring should be suggested for those patients during peri-operative period to optimize surgical stress management.

Access to hip arthroplasty and rates of complications in different socioeconomic groups : a review of 111,000 patients in a universal healthcare system

AIMS

Total hip arthroplasty (THA) is one of the most successful surgical procedures. The objectives of this study were to define whether there is a correlation between socioeconomic status (SES) and surgical complications after elective primary unilateral THA, and investigate whether access to elective THA differs within SES groups.

METHODS

We conducted a retrospective, population-based cohort study involving 202 hospitals in Ontario, Canada, over a 17-year period. Patients were divided into income quintiles based on postal codes as a proxy for personal economic status. Multivariable logistic regression models were then used to primarily assess the relationship between SES and surgical complications within one year of index THA.

RESULTS

Of 111,359 patients who underwent elective primary THA, those in the lower SES groups had statistically significantly more comorbidities and statistically significantly more postoperative complications. While there was no increase in readmission rates within 90 days, there was a statistically significant difference in the primary and secondary outcomes including all revisions due (with a subset of deep wound infection and dislocation). Results showed that those in the higher SES groups had proportionally more cases performed than those in lower groups. Compared to the highest SES quintile, the lower groups had 61% of the number of hip arthroplasties performed.

CONCLUSION

Patients in lower socioeconomic groups have more comorbidities, fewer absolute number of cases performed, have their procedures performed in lower-volume centres, and ultimately have higher rates of complications. This lack of access and higher rates of complications is a "double hit" to those in lower SES groups, and indicates that we should be concentrating efforts to improve access to surgeons and hospitals where arthroplasty is routinely performed in high numbers. Even in a universal healthcare system where there are no penalties for complications such as readmission, there seems to be an inequality in the access to THA. Cite this article: Bone Joint J 2022;104-B(5):589-597.

Prediction of Complications and Surgery Duration in Primary Total Hip Arthroplasty Using Machine Learning: The Necessity of Modified Algorithms and Specific Data

Background: Machine Learning (ML) in arthroplasty is becoming more popular, as it is perfectly suited for prediction models. However, results have been heterogeneous so far. We hypothesize that an accurate ML model for outcome prediction in THA must be able to compute arthroplasty-specific data. In this study, we evaluate a ML approach applying data from two German arthroplasty-specific registries to predict adverse outcomes after THA, after careful evaluations of ML algorithms, outcome and input variables by an interdisciplinary team of data scientists and surgeons. Methods: Data of 1217 cases of primary THA from a single center were derived from two German arthroplasty-specific registries between 2016 to 2019. The XGBoost algorithm was adjusted and applied. Accuracy, sensitivity, specificity and AUC were calculated. Results: For the prediction of complications, the ML algorithm achieved an accuracy of 80.3%, a sensitivity of 31.0%, a specificity of 89.4% and an AUC of 64.1%. For the prediction of surgery duration, the ML algorithm yielded an accuracy of 81.7%, a sensitivity of 58.2%, a specificity of 91.6% and an AUC of 89.1%. The feature importance indicated non-linear outcomes for age, height, weight and surgeon. No relevant linear correlations were found. Conclusion: The attunement of input and output data as well as the modifications of the ML algorithm permitted the development of a feasible ML model for the prediction of complications and surgery duration.

Novel radiographic hip fat thickness ratio correlates with early re-operation following total hip arthroplasty

INTRODUCTION

Obesity is thought to lead to increased failure rates following total hip arthroplasty (THA). Site-specific fat distribution has been suggested to be a better indicator of risk, compared to body mass index. Fat thickness measurement methods were developed for total knee arthroplasty, however, there is limited data on the methods for THA. The aim of this study was to assess the interobserver and intraobserver reliability of a newly defined radiographic subcutaneous fat thickness ratio and investigate the correlation of this ratio with early failure following THA.

METHODS

321 patients who underwent primary THA at a single institution between 2014 and 2017, with at least 1-year of follow-up and a preoperative pelvis anteroposterior x-ray radiograph were included in this study. A high hip fat thickness ratio (HFTR) was arbitrarily defined as ⩾2. Early failure was defined as revision or re-operation for any reason and death related to operation first year following THA.

RESULTS

The HFTR was shown to have excellent intraobserver and interobserver reliability. High HFTR was associated with higher risk of early failure following THA (odds ratio 3.8, [95% confidence interval, 1.2-12.1], p < 0.05). The same association persisted when HFTR was analysed as a continuous variable (p < 0.01) and in multivariate analysis (p < 0.05).

CONCLUSIONS

HFTR can be used to assess periarticular soft tissue distribution and may be regarded as a useful and reproducible tool for assessing risk of early failure following THA.

A Study Investigating Whether BMI Is Associated With Acetabular Bone Size: Big Bones or a Big Myth?

Background

There is a common conception held by patients with a high body mass index (BMI) that they have “big bones”. Some people hold the assumption that their weight is attributed to larger bone stock rather than adipose tissue. It was the suspicion of the surgeons at our unit that this is often not the case. We therefore conducted a study investigating if there is any association between BMI and acetabular bone size.

Methods

We conducted a retrospective chart review of all patients undergoing total hip arthroplasty using the Trident acetabular system from Stryker at our tertiary level 1 trauma centre between September 2016 and August 2020. Patient demographic and surgical data were collected, and the association of BMI, height, and weight, with acetabular cup size was investigated using Pearson’s correlation coefficient and chi-square test for independence.

Results

A total of 418 patients were included in this study (52.4% female; age: 20-93 years; mean age: 62.51 years), with a mean BMI of 29.55 kg/m²(range: 14.95-52.32 kg/m²). A weak positive association between BMI and cup size, which was statistically significant (r = 0.107; n = 418; p = 0.02). The chi-square test for independence was used to study the association between obesity and cup size (large vs small), which demonstrated no significant difference (p = 0.08). There was a moderately strong positive association between height and cup size (r = 0.551; n = 418; p < 0.01). There was a weak positive association between weight and cup size, which was statistically significant (r = 0.355; n = 418; p < 0.01).

Conclusion

Our study suggests that there is indeed a weakly positive linear association between BMI and cup size among total hip arthroplasty patients. This effect was, however, more significant for height and weight, and there was no significant association between obese and non-obese groups with small versus large cup size implanted. We therefore conclude that clinically there is no significant relationship between obesity and acetabular bone size and that the “big bones” claim is indeed fallacious.

Risk analysis of restrictive factors for fast-track hip arthroplasty - a retrospective study of 1138 patients

Fast track programs have been introduced to reduce perioperative complication rates and to quickly reintegrate the patient into everyday life. The aim of this retrospective case-control study was to identify patient characteristics and patient-independent factors that influence fast track programs in hip arthroplasty. A total of 1138 patients were examined. A hospital stay of more than seven days was used to define the case group. In addition to the causes for the longer hospitalisation, age, sex, BMI, chronic nicotine and alcohol abuse, ASA score, surgical duration, anaemia and blood transfusion as well as concomitant diseases were assessed. The statistical analysis included two-sample t-test, chi-square test and logistic regression analyses. An 95% confidence interval was calculated (p<0.05). 16.9% of patients could not leave the hospital on the seventh day. The main causes were delayed wound healing (69.4%), increased CRP (43.0%>100 mg/l), and internal complications (19.7%). At a mean of 69.2 ± 10.7 years, the age of the case group was significantly higher than that of the control group, which had a mean of 63.3 ± 10.3 years (p<0.001). Cardiac comorbidities (p<0.001), BMI (p=0.023), and alcohol consumption (p<0.001) increased the risk for longer hospitalisation. Significant patient-independent factors were duration of the surgery (p<0.001) and transfusion (p<0.001). Successful application of fast-track hip arthroplasty is possible for every patient. However, longer hospi- talisation and delayed discharge must be taken into account for patients with advanced age, cardiac comorbidities, alcohol consumption, and high BMI.

Obesity and Postoperative Complications Following Ankle Arthrodesis: A Propensity Score Matched Analysis

Obese patients undergoing orthopedic procedure have been reported to have higher rates of postoperative complications, but the published associations have numerous confounders. This study aims to evaluate the independent effect of obesity on postoperative complications and hospital utilization following ankle arthrodesis. A database review of a Medicare database was performed on patients less than 85 years old who underwent ankle arthrodesis between 2005 and 2014. Patient cohorts were defined using International Classification of Diseases-9 coding for body mass index (BMI)-obese (30-40 kg/m²), and morbidly obese (>40 kg/m²). Normal BMI patients were defined as those without the respect codes for obesity (30-40 kg/m²), morbidly obese (>40 kg/m²), or underweight (<19 kg/m²). All groups were propensity score matched by demographics and comorbidities. Outcomes of interest included 90-day major and minor medical complications, and hospital burden. Morbid obesity was associated with an increased risk of acute kidney injury (4.4% vs 2.4%, OR 1.94, 95% CI 1.37-2.74, p < .001), urinary tract infection (5.2% vs 3.2%, OR 1.66, 95% CI 1.21-2.25, p = .001), readmission (13.6% vs 10.8%, OR 1.33, 95% CI 1.10-1.61, p = .003), and overall minor complications (16.0% vs 11.8%, OR 1.44, 95% CI 1.19-1.74, p < .001) compared to normal BMI patients, and an increased risk for acute kidney injury (4.4% vs 1.9%, OR 2.25, 95% CI 1.32-3.97, p = .003) compared to obese patients. Obesity was not associated with increased medical complications (p > .05). While morbid obesity was associated with an increase in the postoperative complications, obesity was not associated with any increase in postoperative complications following ankle arthrodesis.

Risk Factors for Mortality After Uncemented Bipolar Hemiarthroplasty for Geriatric Displaced Femoral Neck Fracture

Uncemented bipolar hemiarthroplasty (UBHA) has been widely used to treat geriatric displaced femoral neck fracture (GDFNF), which results in a high 30-day mortality rate among the elderly. To date, few studies have focused on the risk factors for mortality after UBHA for GDFNF. In this retrospective study, elderly patients (age ≥70 years) who underwent UBHA for GDFNF were studied in order to provide helpful insight into the risk factors for mortality postoperatively. This retrospective study enrolled 835 elderly patients who underwent UBHA for GDFNF from January 2010 to December 2017. The Kaplan-Meier method and Cox regression analysis were used to identify significant risk factors predicting mortality after UBHA for GDFNF. Univariate analysis showed that underweight (body mass index <18.5 kg/m²), smoking, alcohol use, hypertension, chronic kidney disease, hypoproteinemia, low activities of daily living (ADL) score (0 to 2), and postoperative delirium were identified as the potential risk factors responsible for mortality after UBHA for GDFNF. Multivariate analysis suggested that underweight, hypoproteinemia, low ADL score, and postoperative delirium were significant risk factors predicting mortality after UBHA for GDFNF. Postoperative delirium was the most robust risk factor for mortality after UBHA for GDFNF. Underweight, hypoproteinemia, and low ADL score were also closely associated with mortality after UBHA for GDFNF. [Orthopedics. 2021;44(4):e570-e576.].

Instability Is the Most Common Indication for Revision Hip Arthroplasty in the United States: National Trends From 2012 to 2018

Background

As primary total hip arthroplasty volume continues to increase, so will the number of revision total hip arthroplasty (rTHA) procedures. These complex cases represent a significant clinical and financial burden to the health-care system.

Methods

This was a retrospective review using the National Inpatient Sample. International Classification of Diseases, 9th and 10^th revision codes were used to identify patients who underwent rTHA and create cohorts based on rTHA indications from 2012 to 2018. National and regional trends for length of stay (LOS), cost, and discharge location were evaluated.

Results

A total of 292,250 rTHA procedures were identified. The annual number of rTHA procedures increased by 28.1% from 2012 to 2018 (37,325 to 47,810). The top 3 indications for rTHA were instability (20.4%), aseptic loosening (17.8%), and infection (11.1%). Over the study period, the proportion of patients discharged to skilled nursing facility decreased from 44.2% to 38% (P < .001). Hospital LOS decreased on average from 4.8 to 4.4 days (P < .001). Infections had the highest average LOS (7.3 days) followed by periprosthetic fractures (6.5 days). Hospital costs decreased over the study period, from $25,794 to $24,555 (P < .001). The proportion of rTHA cases performed at urban academic centers increased (58.0% to 75.3%, P < .001) while the proportion performed at urban nonacademic centers decreased (35.5% to 19.4%, P < .001).

Conclusion

Instability was the most common indication for rTHA between 2012 and 2018. The proportion of rTHA performed in urban academic centers has increased substantially, away from urban nonacademic centers. While cost and LOS have decreased, significant geographic variability exists.

Surgeon Decision-Making for Individuals With Obesity When Indicating Total Joint Arthroplasty

BACKGROUND

Obesity is a risk factor for complications after total joint arthroplasty (TJA). This study analyzed the impact of individual surgeon demographics, financial concerns, and other factors in determining patient candidacy for TJA based on body mass index (BMI).

METHODS

A 21-question survey was approved by the American Association of Hip and Knee Surgeons Research Committee for distribution to its membership. Objective questions asked about surgeon or hospital BMI thresholds for offering TJA. Subjective questions asked about physician comfort discussing topics including obesity, bariatric surgery, and weight loss before TJA, as well as insurance and age considerations.

RESULTS

For TJA procedures, 49.9% of surgeons had a BMI cutoff at 40, 24.5% at 45, and 8.3% at 50. At a BMI cutoff of 40, 23.8% of surgeons felt their patient volume would be adversely affected, whereas at a BMI cutoff of 35, 50% of surgeons felt their patient volume would be adversely affected. Surgeons were more likely to not perform total hip arthroplasty on patients with morbid obesity than total knee arthroplasty (P = .037). Significantly more academic surgeons did not have cutoffs for total hip arthroplasty (P = .003) or total knee arthroplasty (P < .001) compared with all other practice settings.

CONCLUSION

There are myriad factors that affect surgeon BMI thresholds for offering elective TJA including poor outcomes, hospital thresholds, financial considerations, and the well being of the patient. Further work should be performed to minimize the risks associated with TJA while providing the best possible care to patients with morbid obesity.

Increasing Reoperations and Failures With Increasing BMI in Patients Undergoing 2-Stage Exchange for Infected Total Hip Arthroplasty

BACKGROUND

While morbid obesity is associated with increased infection after total hip arthroplasty, little is known on the outcomes after 2-stage reimplantation for prosthetic joint infection (PJI) in this population. The purpose of this study is to evaluate the impact of morbid obesity (body mass index>40 kg/m2) on reinfection, postoperative complications, readmissions, and reoperations.

METHODS

We conducted a retrospective review of 107 patients undergoing first time 2-stage reimplantation for PJI from 2013 to 2019. 18 patients (50% women) with body mass index>40 kg/m2 were identified. To minimize confounders, three propensity score matched cohorts were created, yielding 16 nonobese (<30 kg/m2), 16 obese (30-39.9 kg/m2), and 18 morbidly obese (>40 kg/m2) patients. Outcomes were compared using chi-square or Fisher's exact tests. All patients had minimum 12-month follow-up, with mean follow-up of 36.3, 30.1, and 40.0 months in the nonobese, obese, and morbidly obese cohorts, respectively.

RESULTS

Compared with nonobese patients, morbidly obese patients had a higher rate of reinfection (0% vs 33%, P = .020 and higher likelihood of length of stay>4 days (19% vs 61%, P = .012). In addition, compared with nonobese and obese patients, morbidly obese patients had higher rate of return to the operating room for any reason (13% vs 19% vs 50%, respectively, P = .020). No differences between cohorts were found regarding complications, death, or revision surgery.

CONCLUSION

Morbidly obese patients have significantly increased risk of reinfection and reoperation after 2-stage reimplantation for PJI when compared with obese and nonobese patients. These data can be used to counsel morbidly obese patients contemplating total hip arthroplasty and supports the notion of deferring arthroplasty in this population pending optimization.

The Changing Characteristics of Arthroplasty Patients: A Retrospective Cohort Study

BACKGROUND

Total joint arthroplasty (TJA) is among the most common operations performed worldwide, with global volumes on the rise. It is important to understand if the characteristics of this patient population are changing over time for resource allocation and surgical planning. The purpose of this study is to examine how this patient population has changed between 2003 and 2017.

METHODS

A retrospective review of a prospective TJA database was conducted. Age, gender, body mass index, comorbidities, American Society of Anesthesiologists class, responsible diagnoses, and comorbidities were compared over 5-year intervals between 2003 and 2017. All patients undergoing primary, elective TJA were included.

RESULTS

Overall, 17,138 TJAs were included. Mean body mass index increased over the study period for total hip arthroplasty (THA; 29.4-30.4 kg/m², P < .0001) and total knee arthroplasty (TKA; 32.0-3.1 kg/m², P < .0001) patients. THA patients were significantly younger in more recent years (68.0-66.8 years old, P = .0026); this trend was not observed among TKA patients. Over the study period, a significantly higher proportion of patients were American Society of Anesthesiologists class III/IV for THA (50.5%-72.3%) and TKA (57.5%-80.7%) (P < .00001). Prevalence of common comorbidities did not change significantly.

CONCLUSION

The key findings of this retrospective analysis of a large prospective database are that patients undergoing TJA are becoming younger and more obese. It is unclear whether patients are becoming more medically complex. These trends paint a concerning picture of a population that is increasingly complex, and may require a greater allocation of resources in the future.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Aspirin Use for Venous Thromboembolism Prevention Is Safe and Effective in Overweight and Obese Patients Undergoing Revision Total Hip and Knee Arthroplasty

BACKGROUND

Venous thromboembolism (VTE), defined as pulmonary embolism or deep venous thrombosis, is a rare but serious complication following revision total hip arthroplasty (RTHA) and revision total knee arthroplasty (RTKA). Previous studies show that obesity may be associated with an increased risk for pulmonary embolism, wound complications, and infection. With no current universal standard of care for VTE prophylaxis, we sought to determine whether aspirin prescribed (ASA) is safe and effective in obese patients undergoing RTHA/RTKA.

METHODS

A retrospective review of 1578 consecutive RTHA/RTKA cases (751 RTHAs and 827 RTKAs) was conducted identifying patients prescribed 325 or 81 mg ASA. Ninety-day postoperative VTE rates, bleeding, wound complications, deep infections, and mortality were collected. Cohorts were stratified according to body mass index (BMI): normal (18-24.9 kg/m²), overweight (25-29.9 kg/m²), obese (30-34.9 kg/m²), severely obese (35-39.9 kg/m²), and morbidly obese (≥40 kg/m²).

RESULTS

The cohort comprised of 335 patients with a normal BMI, 511 were overweight, 408 obese, 232 severely obese, and 92 morbidly obese. Total VTE rates were statistically similar between BMI groups (0.90% vs 0.78% vs 0.74% vs 0.43% vs 0%, P = .89). There were no differences in bleeding rates (0.90% vs 0% vs 0% vs 0.43% vs 0%, P = .08), wound complications (0.30% vs 0.20% vs 0.25% vs 0% vs 0%, P = .93), infection (1.49% vs 1.57% vs 0.98% vs 1.29% vs 1.09%, P = .66), or mortality (0% vs 0.20% vs 0% vs 0% vs 0%, P = .72).

CONCLUSION

ASA is safe and effective for VTE prevention in obese patients with similar complication rates to nonobese patients undergoing RTHA/RTKA.

Should isolated morbid obesity influence the decision to operate in hip and knee arthroplasty?

AIMS

We studied the outcomes of hip and knee arthroplasties in a high-volume arthroplasty centre to determine if patients with morbid obesity (BMI ≥ 40 kg/m²) had unacceptably worse outcomes as compared to those with BMI < 40 kg/m².

METHODS

In a two-year period, 4,711 patients had either total hip arthroplasty (THA; n = 2,370), total knee arthroplasty (TKA; n = 2,109), or unicompartmental knee arthroplasty (UKA; n = 232). Of these patients, 392 (8.3%) had morbid obesity. We compared duration of operation, anaesthetic time, length of stay (LOS), LOS > three days, out of hours attendance, emergency department attendance, readmission to hospital, return to theatre, and venous thromboembolism up to 90 days. Readmission for wound infection was recorded to one year. Oxford scores were recorded preoperatively and at one year postoperatively.

RESULTS

On average, the morbidly obese had longer operating times (63 vs 58 minutes), longer anaesthetic times (31 vs 28 minutes), increased LOS (3.7 vs 3.5 days), and significantly more readmissions for wound infection (1.0% vs 0.3%). There were no statistically significant differences in either suspected or confirmed venous thromboembolism. Improvement in Oxford scores were equivalent.

CONCLUSION

Although morbidly obese patients had less favourable outcomes, we do not feel that the magnitude of difference is clinically significant when applied to an individual, particularly when improvement in Oxford scores were unrelated to BMI. Cite this article: Bone Jt Open 2021;2(7):515-521.

Instability After Total Hip Arthroplasty and the Role of Advanced and Robotic Technology

Instability remains the leading cause of reoperation following total hip arthroplasty (THA). In this article, the risk factors for instability after THA are reviewed, including patient-related characteristics, surgical techniques, positioning of implants, and the role of advanced technology and robotics as a platform that may reduce the incidence of instability.