Delineating the impact of obesity and its relationship on recovery after total joint arthroplasties

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.

Epidemiological Characteristics and Trends of Primary Hip Arthroplasty in Five Tertiary Hospitals: A Multicenter Retrospective Study

OBJECTIVE

The number of primary hip arthroplasty (PHA) has increased sharply in recent years. Whether the epidemiological characteristics and trends of PHA have changed are unknown. This study aims to analyze the epidemiological characteristics and trends of those patients are urgent for public health institutions.

METHODS

The data of patients who underwent PHA in five tertiary hospitals from January 2011 to December 2020 were retrospectively reviewed. A total of 21,898 patients were included, most of whom were aged 60-69 years (25.1% males and 31.5% females). According to the hospitalization date, the patients were divided into two groups (Group A and Group B). The patients admitted between January 2011 and December 2015 were designated as Group A (7862), and those admitted between January 2016 and December 2020 were designated as Group B (14036). The patient data of the two groups, including sex, age, disease causes, body mass index (BMI), comorbidities, surgical procedures, hospital stay duration, and hospitalization costs, were analyzed by Pearson chi-Square test, Student t test or Mann-Whitney U test.

RESULTS

More women were included in Group B than in Group A (58.5% vs 52.5%, P < 0.001). The mean age of Group B was less than that of Group A (62.27 ± 14.77 vs 60.69 ± 14.44 years, P < 0.001). Femoral head necrosis was the primary pathogenic factor in both groups, with a higher proportion in Group B than in Group A (55.5% vs 45.5%, P < 0.001). Significant differences were found between the two groups in BMI, comorbidities, surgical procedures, hospital stay duration, and hospitalization costs. Total hip arthroplasty (THA) was the most common surgical procedure in both groups, with a higher proportion in Group B than in Group A (89.8% vs 79.3%, P < 0.001). The proportion of patients with one or more comorbidities was significantly higher in Group B than in Group A (69.2% vs 59.9%, P < 0.001). In addition, Group B had a shorter hospital stay duration and higher hospitalization costs than Group A.

CONCLUSION

Femoral head necrosis was the primary etiology for PHA in this study, followed by femoral neck fracture and hip osteoarthritis. Patients who underwent PHA exhibited a higher percentage of femoral head necrosis; underwent THA more often; and had larger BMIs, more comorbidities, higher medical costs, and younger age in the past decade.

Preoperative Lower-Limb Muscle Predictors for Gait Speed Improvement after Total Hip Arthroplasty for Patients with Osteoarthritis

This study aimed to identify preoperative lower-limb muscle predictors for gait speed improvement after total hip arthroplasty (THA) with hip osteoarthritis. Gait speed improvement was evaluated as the subtraction of preoperative speed from postoperative speed. The preoperative muscle composition of ipsilateral hip abductors was evaluated using computed tomography. The females (n = 45) showed smaller total cross-sectional areas of the gluteal muscles than the males (n = 13). The gluteus maximus in the females showed lower lean muscle mass area (LMM) and higher ratios of the intramuscular fat area and the intramuscular adipose tissue area to the total muscle area (TM) than the males. Regression analysis revealed that LMM/TM of the glutei medius and minimus may correlate negatively with postoperative improvement in gait speed. Receiver operating characteristic curve analysis for prediction of minimum clinically important improvement in gait speed at ≥0.32 m/s resulted in the highest area under the curve for TM in the upper portion of the gluteus maximus with negative correlation. The explanatory variables of hip abductor muscle composition predicted gait speed improvement after THA more precisely in the females compared with the total group of both sexes. Preoperative muscle composition should be evaluated separately based on sex for the achievement of clinically important improvement in gait speed after THA.

Risk factors for pain after total hip arthroplasty: a systematic review

BACKGROUND

Approximately 23% of patients develop hip pain after total hip arthroplasty (THA). In this systematic review, we aimed to identify risk factors associated with postoperative pain after THA to optimize preoperative surgical planning.

METHODS

Six literature databases were searched for articles published from January 1995 to August 2020. Controlled trials and observational studies that reported measurements of postoperative pain with assessments of preoperative modifiable and non-modifiable risk factors were included. Three researchers performed a literature review independently.

RESULTS

Fifty-four studies were included in the study for analysis. The most consistent association between worse pain outcomes and the female sex is poor preoperative pain or function, and more severe medical or psychiatric comorbidities. The correlation was less strong between worse pain outcomes and preoperative high body mass index value, low radiographic grade arthritis, and low socioeconomic status. A weak correlation was found between age and worse pain outcomes.

CONCLUSIONS

Preoperative risk factors that were consistently predictive of greater/server postoperative pain after THA were identified, despite the varying quality of studies that prohibited the arrival of concrete conclusions. Modifiable factors should be optimized preoperatively, whereas non-modifiable factors may be valuable to patient education, shared decision-making, and individualized pain management.

Influence of body mass index on early post-operative functional outcomes after total knee arthroplasty: A prospective, clinical and observational study

Background/Purpose: The evidence on the influence of body mass index (BMI) on functional outcomes following total knee arthroplasty (TKA) is conflicting. This study assessed and compared the effect of BMI on early mobility and function after TKA. Methods: Adult patients with osteoarthritis (OA) or rheumatoid arthritis (RA) who received unilateral TKA were recruited and then divided into normal, overweight and obese groups. The pain and functional outcomes of pre/post-TKA were examined using visual analogue scale (VAS) and Lysholm Knee Scale (LKS), respectively. Results: At 3 and 6 weeks post-TKA, LKS score was significantly higher in normal BMI group compared to overweight and obese. Lower BMI gained early improvement in functional outcome than higher BMI groups. However, patients showed considerable functional improvement at 6 months post-TKA, regardless of BMI category. Conclusion: Although BMI levels influence postoperative early functional improvement in TKA patients, the functional benefits after TKA at 6 months were similar regardless of BMI class.

Changes in epidemiological characteristics of knee arthroplasty in eastern, northern and central China between 2011 and 2020

OBJECTIVE

To explore changes in the epidemiological and clinical characteristics of patients who underwent knee arthroplasty (KA) over a 10-year period in China.

METHODS

Medical records of patients with knee osteoarthritis (KOA), who underwent primary unilateral KA in 5 level I center hospitals in China between January 2011 and December 2020, were retrospectively reviewed and analyzed. To more clearly define changes over the years, patients were divided into two groups according to time of admission at 5-year intervals. Age, sex, body mass index (BMI), Kellgren-Lawrence (K-L) classification, comorbid diseases, surgical procedures, hospital stay, and hospitalization costs were compared between the two groups.

RESULTS

A total of 23,610 patients with KOA (5400 male and 18,210 females; mean age: 65.7 ± 7.6 years) who underwent primary unilateral KA were included. The number of KAs increased in recent years (group A, n = 7606 vs. group B, n = 16,004). Significant differences were noted in age, sex, BMI, K-L classification, comorbidities, surgical procedures, hospital stay, and hospitalization costs between the two periods (P < 0.05). More than three-quarters of KA cases involved females, and the age at surgery tended to be younger than that reported in foreign countries. In group B, the proportion of overweight and grade III, number of comorbidities, and unicompartmental knee arthroplasty patients increased compared to that in group A; however, hospitalization costs and length of hospital stay decreased.

CONCLUSIONS

Results suggested that the epidemiological characteristics of patients undergoing KA have changed over time. An analysis of the epidemiological characteristics of patients undergoing KA treatment may provide a scientific basis for the prevention and control of KOA.

Functional recovery after total hip/knee replacement in obese people: A systematic review

OBJECTIVE

Several studies have investigated the influence of body mass index (BMI) on functional gain after total hip replacement (THR) or total knee replacement (TKR) in osteoarthritis, with contradictory results. This systematic literature review was conducted to ascertain whether obesity affects functional recovery after THR or TKR in the short (<1 year), medium (<3 years) and long term (>3 years).

METHODS

The study was registered with PROSPERO and conducted according to the PRISMA guidelines. A systematic literature search was conducted across Medline and EMBASE databases for articles published between 1980 and 2020 that investigated patient-reported measures of functional recovery after THR and TKR in participants with osteoarthritis and obesity (defined as BMI ≥30 kg/m²).

RESULTS

Twenty-six articles reporting on 68,840 persons (34,955 for THR and 33,885 for TKR) were included in the final analysis: 5 case-control studies, 21 cohort studies (9 for THR only, 10 for TKR only and 2 for both). The average minimum follow-up was 36.4 months, ranging from 6 weeks to 10 years. Most studies found significantly lower pre-operative patient-reported functional scores for participants with obesity. After THR, there was a small difference in functional recovery in favor of those without obesity in the short term (<6 months), but the difference remained below the minimal clinically important difference (MCID) threshold and disappeared in the medium and long term. After TKR, functional recovery was better for those with obesity than those without in the first year, similar until the third year, and then decreased thereafter.

CONCLUSIONS

Although there is a paucity of high-quality evidence, our findings show substantial functional gains in people with obesity after total joint replacement. Functional recovery after THR or TKR does not significantly differ, or only slightly differs, between those with and without obesity, and the difference in functional gain is not clinically important.

PROSPERO NUMBER

CRD42018112919.

Association of preoperative variables of ipsilateral hip abductor muscles with gait function after total hip arthroplasty: a retrospective study

Background

This study aimed to identify the association of preoperative variables of ipsilateral hip abductors with gait function after total hip arthroplasty (THA).

Methods

This study enrolled 42 patients who underwent unilateral primary THA for osteoarthritis. Gait speed and Timed Up-and-Go test were conducted 6 months postoperatively. Preoperative composition of the glutei medius and minimus and the upper portion of gluteus maximus was evaluated by computed tomography. Cross-sectional area ratio of individual composition to the total muscle was calculated. Preoperative variables associated with gait speed and Timed Up-and-Go test after THA were identified by using stepwise regression analysis.

Results

Faster gait speed and shorter Timed Up-and-Go test correlated with smaller cross-sectional area of low-density lean tissue or intramuscular adipose tissue (low-density lean tissue plus intramuscular fat) in the glutei medius and minimus and lower cross-sectional area ratio of low-density lean tissue to the total glutei medius and minimus. Faster gait speed and shorter Timed Up-and-Go test also correlated with larger cross-sectional area of lean muscle mass in the gluteus maximus, higher cross-sectional area ratio of lean muscle mass to the total gluteus maximus, and lower cross-sectional area ratio of intramuscular fat or intramuscular adipose tissue to the total gluteus maximus. Faster gait speed additionally correlated with larger total cross-sectional area of the gluteus maximus. Regression analysis showed that the total cross-sectional area of the gluteus maximus and the low-density lean tissue cross-sectional area of the glutei medius and minimus were the explanatory variables of gait speed and Timed Up-and-Go test after THA, respectively.

Conclusions

There was a potential association between preoperative composition of ipsilateral hip abductors and gait function 6 months after THA. This study indicates a predictive role of preoperative assessment of ipsilateral hip abductor composition in the recovery of gait function after THA.

Effect of Weight Change on Patient-Reported Outcomes Following Total Joint Arthroplasty

BACKGROUND

Increased body mass index (BMI) has been previously described as a risk factor for complications after total joint arthroplasty (TJA); however, its effect on patient-reported outcomes has not been thoroughly investigated. This study examines the effect of postoperative weight change on the Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF) scores for total knee arthroplasty (TKA) and total hip arthroplasty (THA) patients.

METHODS

A retrospective review of 988 patients undergoing THA or TKA was performed. PROMIS-PF scores and BMI were recorded throughout the study duration. Patients were classified by a 5% change in BMI. A univariate analysis evaluated differences across groups. Mixed-effect models evaluated predictors of change in functional score over the postoperative follow-up time.

RESULTS

43.1% patients had a THA and 56.9% patients had a TKA. At 0 to 3 months, 92% of patients had no change in BMI, 3 to 6 months 82% had no change, and 6 to 12 months 80% had no change. There were no significant demographic or comorbidity differences across groups for both THA and TKA. Similar improvements in PROMIS-PF scores were observed across weight change groups. In the mixed-effect models, postoperative time was found to be a significant predictor of postoperative PF score. Both THA and TKA patients saw greater improvements in PROMIS-PF scores in patients with lower preoperative BMIs.

CONCLUSION

These results demonstrate most patients do not experience substantial changes in weight following TJA. However, lower BMIs at the time of surgery were associated with an increased functional improvement. Therefore, efforts to optimize BMI should be focused preoperatively to improve surgical outcomes.

Diabesity: a superadded effect contributing to worse total primary hip replacement operative outcomes for patients with diabetes and obesity

INTRODUCTION

Although the independent effects of diabetes mellitus and obesity on total hip replacement (THR) outcomes have been widely studied, their combined effect remains uncharacterised. This study aimed to assess the influence of diabesity on primary THR operative outcomes.

MATERIALS AND METHODS

A retrospective study was performed comparing the outcomes of patients with diabesity (diabetes mellitus and obesity [BMI ≥ 30]) with a control cohort after primary THR using an established arthroplasty database. Data were collected pre-operatively and 12 months post-operatively, including Oxford Hip Score (OHS), EuroQol 5-dimensions (EQ5D), post-operative satisfaction and complication rates.

RESULTS

2323 THRs were analysed, of which 94 (4%) had diabesity. Diabesity was independently associated with significantly worse OHS improvement post-operatively (- 1.85 points, 95% CI - 2.93 to - 0.76, p = 0.001). This reduction in addition to the independent effect of obesity (- 0.69 points, 95% CI - 1.18 to - 0.21, p = 0.005) resulted in an overall 2.54 point OHS reduction for patients with diabesity. Diabesity was not associated with EQ5D score change or post-operative satisfaction. Diabesity was independently associated with a worse pre-operative EQ5D score (-0.08 points, 95% CI -0.12 to -0.03, p = 0.002). When combining the associated risk of obesity (Odds Ratio (OR) 1.71, 95% CI 1.15-2.54, p = 0.008) with the superadded effect of diabesity (OR 2.37, 95% CI 1.19-4.71, p = 0.014) the rate of superficial wound infection post-operatively was significantly increased (OR 4.05, 95% CI 1.38-11.95). Obesity was associated with a significantly increased risk of deep infection (OR 3.67, 95% CI 1.55-8.68, p = 0.003), but no additive effect of diabetes was found.

CONCLUSIONS

Diabesity confers a superadded effect over established associations between THR outcomes and obesity and diabetes individually. Patients with diabesity experience worse improvement in hip-specific functional outcome, worse post-operative quality of life, and an increased risk of superficial and deep wound infection following THR.

Association Between Nonsurgical Weight Loss From Body Mass Index >40 to Body Mass Index <40 and Complications and Readmissions Following Total Hip Arthroplasty

BACKGROUND

Elevated body mass index (BMI) is a risk factor for adverse outcomes following total hip arthroplasty (THA). It is unknown if preoperative weight loss to a BMI <40 kg/m² is associated with reduced risk of adverse outcomes.

METHODS

We retrospectively reviewed elective, primary THA performed at an academic center from 2015 to 2019. Patients were split into groups based on their BMI trajectory prior to THA: BMI consistently <40 ("BMI <40"); BMI >40 at the time of surgery ("BMI >40"); and BMI >40 within 2 years preoperatively, but <40 at the time of surgery ("Weight Loss"). Length of stay (LOS), 30-day readmissions, and complications as defined by Centers for Medicare and Medicaid Services were compared between groups using parsimonious regression models and Fisher's exact testing. Adjusted analyses controlled for sex, age, and American Society of Anesthesiologists class.

RESULTS

In total, 1589 patients were included (BMI <40: 1387, BMI >40: 96, Weight Loss: 106). The rate of complications in each group was 3.5%, 6.3%, and 8.5% and the rate of 30-day readmissions was 3.0%, 4.2%, and 7.5%, respectively. Compared to the BMI <40 group, the weight loss group had a significantly higher risk of 30-day readmission (odds ratio [OR] 2.70, 95% confidence interval [CI] 1.19-6.17, P = .02), higher risk of any complication (OR 2.47, 95% CI 1.09-5.59, P = .03), higher risk of mechanical complications (OR 3.07, 95% CI 1.14-8.25, P = .03), and longer median LOS (16% increase, P = .002). The BMI >40 group had increased median LOS (10% increase, P = .03), but no difference in readmission or complications (P > .05) compared to BMI <40.

CONCLUSION

Weight loss from BMI >40 to BMI <40 prior to THA was associated with increased risk of readmission and complications compared to BMI <40, whereas BMI >40 was not.

LEVEL OF EVIDENCE

Level III - Retrospective Cohort Study.

Clinical Course of Pain and Function Following Total Knee Arthroplasty: A Systematic Review and Meta-Regression

BACKGROUND

Total knee arthroplasty (TKA) is widely considered a successful intervention for osteoarthritis and other degenerative knee diseases. This study addresses the need for a high-quality meta-analysis that outlines the clinical course of pain and function post-TKA.

METHODS

The review included prospective cohort studies assessing pain or function of patients undergoing primary TKA at baseline (preoperatively) and at least 2 additional time points including one at least 12 months postoperatively. Two reviewers independently screened references, extracted data, and assessed risk of bias using the Quality in Prognosis Studies tool. The time course of recovery of pain and function was modeled using fractional polynomial meta-regression.

RESULTS

In total, 191 studies with 59,667 patients were included, most with low risk of bias. The variance-weighted mean pain score (/100, 0 = no pain) was 64.0 (95% confidence interval [CI] 60.2-67.7) preoperatively, 24.1 (95% CI 20.3-27.9) at 3 months, 20.4 (95% CI 16.7-24.0) at 6 months, and 16.9 (95%CI 13.6-20.3) at 12 months, and remained low (10.1; 95% CI 4.8-15.4) at 10 years postoperatively. The variance-weighted mean function score (/100, 0 = worst function) was 47.1 (95% CI 45.7-48.4) preoperatively, 72.8 (95% CI 71.3-74.4) at 3 months, 76.3 (95% CI 74.7-77.8) at 6 months, and 78.1 (95%CI 76.4-79.7) at 12 months. Function scores were good (79.7; 95% CI 77.9-81.5) at 10 years postoperatively.

CONCLUSION

Patients undergoing primary TKA can expect a large and rapid but incomplete recovery of pain and function in the first postoperative year. At 10 years, the gains in pain scores may still remain while there is an improvement in function.

The Association of Body Mass Index with Surgical Time Is Mediated by Comorbidity in Patients Undergoing Total Hip Arthroplasty

Overweight represents a major issue in contemporary orthopaedic practice. A higher body mass index (BMI) is associated with an increase of perioperative complications following several orthopaedic procedures, in particular total hip arthroplasty (THA). However, the influence of overweight on THA surgical time is controversial. In this study, we investigated the association between BMI and surgical time analyzing the role of patients’ comorbidities. We conducted a retrospective study on 748 patients undergoing THA at our institutions between 2017 and 2018. Information regarding medical diseases was investigated and the burden of comorbidity was quantified using the Charlson score (CCI). Surgical time and blood loss were also recorded. Median surgical time was 76.5 min. Patients with surgical time above the median had both a higher BMI (28.3 vs. 27.1 kg/m²; p = 0.002); and CCI (1 vs. 0; p = 0.016). According to linear regression, surgical time was associated with BMI in the unadjusted model (p < 0.0001), after adjusting for age and sex (p < 0.0001), and in the multivariable model (p = 0.005). Furthermore, BMI was associated with increased surgical time only in patients with a Charlson score above the median, but not in others. Obesity is associated with increased surgical time during THA, especially in pluricomorbid patients, with a higher risk of perioperative complications.

Weight Loss in Patients Waiting for Total Hip Arthroplasty: Fiber-Enriched High Carbohydrate Diet Improves Hip Function and Decreases Pain before Surgery

The impact of obesity on clinical outcomes following joint replacement procedures is resounding. Therefore, multiple strategies to achieve a substantial weight loss before surgery are needed in obese patients. The aim of the study was to test the effect of a fiber-enriched high carbohydrate (FEHC) diet on the reduction in body weight and pain in elderly obese patients undergoing total hip arthroplasty (THA). Sixty-one candidates for THA were included in our study. Prior to the procedure, the participants have been randomly assigned to a 3-month diet intervention (FEHC diet or free diet). Anthropometric measures and food questionnaires were collected at the enrollment and after 3 months. The Oxford Hip Score (OHS), the Hip disability and Osteoarthritis Outcome Score (HOOS) and the Western Ontario McMaster Universities OA Index (WOMAC) were administered at baseline and before surgery. A statistically significant variation of weight was found in the FEHC diet group (-3.7 kg, -4.4--2.5) compared to the control group (-0.2 kg; -1.4-1.7; p < 0.0001), as well as significant improvements in the OHS (p < 0.0001), the HOOS (p < 0.0001) and the WOMAC (p < 0.0001) questionnaires. According to the results of the study, the FEHC diet in obese patients undergoing THA might help weight loss and improve related anthropometric parameters as well as hip function and pain.

Greater risk of all-cause revisions and complications for obese patients in 3 106 381 total knee arthroplasties: a meta-analysis and systematic review

BACKGROUND

Obesity is a major public health issue and has considerable implications on outcomes of total knee arthroplasty (TKA). However, there has been conflicting evidence and conclusions on the effects of obesity on TKA. This meta-analysis compares the outcomes, complications, and peri-operative parameters of TKA in the obese (body mass index [BMI] ≥ 30 kg/m² ) versus non-obese (BMI < 30 kg/m² ) population as well as subgroup analysis of morbidly obese (BMI ≥ 40 kg/m² ) versus non-obese population.

METHODS

A meta-analysis was conducted with a multi-database search according to PRISMA guidelines on 12 September 2019. Data from all published literature meeting inclusion criteria were extracted and analysed.

RESULTS

Ninety-one studies were included, consisting of 917 447 obese and 2 188 834 non-obese TKA. Obese patients had higher risk of all-cause revisions (odds ratio [OR] = 1.15, 95% CI: 1.08-1.24, p < 0.0001), all complications (OR = 1.21, 95% CI: 1.06-1.38, p = 0.004), deep infections (OR = 1.47, 95% CI: 1.27-1.69, p < 0.0001), superficial infections (OR = 1.59, 95% CI: 1.32-1.91, p < 0.0001), wound dehiscence (OR = 1.46, 95% CI: 1.24-1.72, p < 0.0001) and readmissions (OR = 1.21, 95% CI: 1.05-1.40, p = 0.009). Subgroup analysis of morbidly obese patients revealed greater risks of all-cause revisions (OR = 1.25, 95% CI: 1.10-1.43, p = 0.0009), deep infections (OR = 1.98, 95% CI: 1.05-3.75, p = 0.04), superficial infections (OR = 2.44, 95% CI: 2.08-2.88, p < 0.0001) and readmissions (OR = 1.33, 95% CI: 1.20-1.47, p < 0.0001). No analysis was performed on patient reported outcome measures due to heterogeneous reporting methods.

CONCLUSION

Obese and morbidly obese patients have higher risks of revisions and infections post TKA. Surgeons should counsel patients of these risks during the informed consenting process and adopt preventative strategies into clinical practice to reduce risks where possible. In conclusion, obesity is a significant, modifiable risk factor for increased complications following TKA.

Gait mechanics are influenced by quadriceps strength, age, and sex after total knee arthroplasty

Although most patients are satisfied with outcomes after total knee arthroplasty (TKA), many retain preoperative altered gait mechanics. Identifying patient characteristics associated with gait mechanics will improve rehabilitation strategies and enhance our understanding of movement disorders. Therefore, the purpose of this study was to identify which patient characteristics are related to gait mechanics in the surgical limb during walking post-TKA. Patient characteristics included age, body mass, sex, quadriceps strength, self-reported function, and knee pain. General linear regression was used to compare patient characteristics associated with gait mechanics, after controlling for gait speed, functional capacity and time from surgery. We tested 191 patients cross-sectionally at 6-24 months after primary, unilateral TKA. Quadriceps weakness in the surgical limb was associated with less peak vertical ground reaction force (PvGRF) (β = .245, p = .044), knee extension moment (β = .283, p = .049), and knee extension excursion (β = .298, p = .038). Older age (β = .168, p = .050) was associated with less PvGRF. Quadriceps strength in the nonsurgical limb (β = -.357, p = .021) was associated with greater knee extension excursion in the surgical limb. Females with TKA (β = -.276, p = .007) had less knee flexion excursion compared to males. Faster gait speed was also associated with greater PvGRF (β = .585, p < .001), knee extensor moment (β = .481, p < .001), and knee flexion excursion (β = .318, p < .001). Statement of Clinical Significance: This study showed quadriceps weakness, slower gait speed, older age and being female were related to altered gait mechanics post-TKA. These findings will help clinicians better educate patients and develop targeted interventions for improving care in patients post-TKA.

Diabetes Mellitus Blunts the Symptoms, Physical Function, and Health-Related Quality of Life Benefits of Total Knee Arthroplasty: A Systematic Review With Meta-analysis of Data From More Than 17 000 Patients

OBJECTIVE

To compare physical function, pain, impairments (stiffness, range of motion, and strength), and health-related quality of life (HRQoL) outcomes between patients with and without diabetes mellitus, before and after a total knee arthroplasty (TKA).

DESIGN

Prognosis systematic review.

LITERATURE SEARCH

We searched MEDLINE/PubMed, CINAHL, SPORTDiscus, and Web of Science to August 2019.

STUDY SELECTION CRITERIA

We included longitudinal studies that examined physical function, pain, impairments, and HRQoL outcomes among patients receiving a TKA and with or without diabetes.

DATA SYNTHESIS

For quantitative synthesis, we stratified outcomes based on time relative to TKA: preoperative, less than 1 year after a TKA (early postoperative), and 1 year or more after a TKA (late postoperative). We used random-effects meta-analysis to calculate standardized mean differences (SMDs) and 95% confidence intervals (CIs). We used the Grading of Recommendations Assessment, Development and Evaluation system for qualitative synthesis.

RESULTS

We included 21 studies (n = 17 472 patients). Patients with diabetes mellitus had worse preoperative physical function (SMD, -0.16; 95% CI: -0.24, -0.08) and HRQoL (SMD, -0.16; 95% CI: -0.26, -0.05), worse early postoperative pain (SMD, -0.22; 95% CI: -0.39, -0.05) and strength (SMD, -0.45; 95% CI: -0.77, -0.14), and worse late postoperative physical function (SMD, -0.23; 95% CI: -0.40, -0.06), range of motion (SMD, -0.23; 95% CI: -0.46, 0.00), and HRQoL (SMD, -0.19; 95% CI: -0.29, -0.08) than patients without diabetes mellitus. The overall risk of bias across studies was high, and the certainty of evidence ranged from low to very low.

CONCLUSION

Patients with diabetes mellitus had worse patient-reported and clinician-assessed outcomes before and after a TKA. Given the limitations of included studies, these results may change with future research. J Orthop Sports Phys Ther 2021;51(6):269-280. Epub 19 Apr 2021. doi:10.2519/jospt.2021.9515.

Impact of Obesity on the Forgotten Joint Score Following Primary Total Hip Arthroplasty

BACKGROUND

Obesity is a growing public health concern. This study aims to identify the association of body mass index (BMI) on postoperative Forgotten Joint Score-12 (FJS-12) in patients undergoing primary total hip arthroplasty (THA).

METHODS

We retrospectively reviewed 2130 patients at a single urban, academic, tertiary institution who underwent primary THA from 2016-2020 with available postoperative FJS-12 scores. Patients were stratified into two groups based on their BMI (kg/m²):<30 (nonobese) and ≥30 (obese). FJS-12 scores were collected postoperatively at 3 months, 1 year, and 2 years. Demographic differences were assessed with chi-square and independent sample t-tests. Mean scores between the groups were compared using multilinear regression analysis, controlling for demographic differences.

RESULTS

Of the 2130 patients included, 1378 were nonobese, and 752 were obese. Although obese patients reported lower FJS-12 scores all time periods, there were no statistical differences between the two groups at 3 months (53.61 vs 49.62;P = .689), 1 year (68.11 vs 62.45; P = .349), and 2 years (73.60 vs 65.58; P = .102). A subanalysis comparing patients who were of normal BMI (<25), overweight (25.0-29.9), and obese (≥30) followed a similar inverse trend in scores but showed no statistical differences at all postoperative time points (3m:P = .612,1y:P = .607,2y:P = .253). Mean improvement in FJS-12 scores from 3 months to 1 year (14.50 vs 12.83; P = .041), 1 year to 2 years (5.49 vs 3.13; P = .004), and from 3 months to 2 years (20.00 vs15.96; P < .001) were significantly greater for nonobese patients compared to obese patients.

CONCLUSION

While obesity trended toward lower FJS-12 scores, the differences in scores were not statistically significant compared to nonobese patients. BMI did not influence overall FJS-12 scores; however, obese patients achieved a slightly smaller statistical improvement during the first 2 years, though this may not be clinically significant.

LEVEL III EVIDENCE

Retrospective Cohort Study.

Complication rates and resource utilization after total hip and knee arthroplasty stratified by body mass index

Over 295,000 patients from 2016 to 2018 in a national database were grouped into normal weight (BMI 18.5 to <25 kg/m²), overweight (25 to <30), type-1 obese (30 to <35), type-2 obese (35 to <40), and type-3 obese (40 or higher). Differences in resource utilization and complication rates across BMI categories were compared. In comparison to normal weight patients, overweight and obese patients undergoing TJA were at risk for increased resource utilization and various early complications. Patients undergoing TKA with a BMI up to 45 kg/m² are at similar risk for 30-day postoperative complications when compared to type-1 obese patients.

Diabetes Status Affects Odds of Body Mass Index-dependent Adverse Outcomes After Total Hip Arthroplasty

INTRODUCTION

Obesity and diabetes have independently been shown to predispose to adverse outcomes after total hip arthroplasty (THA). These may have a coupled effect on perioperative risks. The purpose of this study was to evaluate the effect of body mass index (BMI) on adverse outcomes in nondiabetic (ND), non-insulin-dependent diabetes mellitus (NIDDM), and insulin-dependent diabetes mellitus (IDDM) patients.

METHODS

Patients undergoing primary THA were selected from the National Surgical Quality Improvement Program Database from 2012 to 2016 and categorized as ND, NIDDM, and IDDM. BMI, demographics, and 30-day perioperative outcomes were assessed for each group. Multivariate logistic regressions controlling for demographics, functional status, and American Society of Anesthesiologists were used to determine the odds ratio of serious adverse event (SAE) in each diabetes group for patients with BMI ≥ 40 kg/m compared with a control group of ND patients with a normal BMI (18.5 to 24.9 kg/m).

RESULTS

A total of 108,177 patients were included. The results demonstrate that ND (odds ratio 1.65; P < 0.001) and NIDDM (odds ratio 1.75; P = 0.007) patients have similar risks of SAE, whereas IDDM (odds ratio 2.79; P < 0.001) patients have a greater risk of adverse events, particularly at BMIs greater than 40 kg/m.

DISCUSSION

Consistent with previous reports, ND (odds ratio 1.65; P < 0.001) and NIDDM (odds ratio 1.75; P = 0.007) morbidly obese patients (BMI > 40 kg/m) had an increased odds of SAEs after THA, but for IDDM (odds ratio 2.79; P < 0.001) patients this increased odds was notably higher. Although patients with IDDM have increased rates of adverse events compared with ND and NIDDM patients, these findings should not be used to establish strict BMI cutoffs in patients with IDDM. Nonetheless, the results suggest additional factors, such as patient medical history and diabetes control, should be considered when evaluating patients with IDDM for THA.

LEVEL OF SIGNIFICANCE

Level III.

Revision Rates and Functional Outcomes Among Severely, Morbidly, and Super-Obese Patients Following Primary Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Obesity has been associated with a greater burden of symptomatic knee osteoarthritis. There is some evidence that patients with a very high body mass index (BMI) may have a higher risk of complications and poor outcomes following total knee replacement compared with non-obese patients or obese patients with a lower BMI. We hypothesized that increasing degrees of obesity would be associated with deteriorating outcomes for patients following total knee replacement.

METHODS

We performed a comprehensive systematic review of 4 medical databases (MEDLINE, AMED, Ovid Healthstar, and Embase) from inception to August 2016. We extracted data to determine revision risk (all-cause, septic, and aseptic) and functional outcome scores (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], Knee Society Score, Oxford Knee Score, EuroQol-5D, and Short Form [SF]-12 Physical Component Summary) in patients with severe obesity (BMI ≥35 kg/m), morbid obesity (BMI ≥40 kg/m), and super-obesity (BMI ≥50 kg/m) in comparison with patients with a normal BMI (<25 kg/m). Meta-analysis was performed using a random effects model.

RESULTS

We screened 3,142 titles and abstracts and 454 full-text articles to identify 40 eligible studies, of which 37 were included in the meta-analysis. Compared with patients with a normal BMI, the risk ratio for an all-cause revision surgical procedure was 1.19 (95% confidence interval [CI], 1.03 to 1.37; p = 0.02) in patients with severe obesity, 1.93 (95% CI, 1.27 to 2.95; p < 0.001) in patients with morbid obesity, and 4.75 (95% CI, 2.12 to 10.66; p < 0.001) in patients with super-obesity. The risk ratio for septic revision was 1.49 (95% CI, 1.28 to 1.72; p < 0.001) in patients with severe obesity, 3.69 (95% CI, 1.90 to 7.17; p < 0.001) in patients with morbid obesity, and 4.58 (95% CI, 1.11 to 18.91; p = 0.04) in patients with super-obesity. There were no significant differences (p > 0.05) in risk of aseptic revision. Based on the Knee Society Scores reported in a single study, patients with super-obesity had outcome scores, expressed as the standardized mean difference, that were 0.52 lower (95% CI, 0.80 lower to 0.24 lower; p < 0.001) than non-obese controls; however, no difference was observed for severe or morbidly obese patients.

CONCLUSIONS

The risk of septic revision is greater in patients with severe obesity, morbid obesity, and super-obesity, with progressively higher BMI categories associated with a higher risk. However, the risk of aseptic revision was similar between all obese and non-obese patients. Functional outcome improvements are also similar, except for super-obese patients, in whom data from a single study suggested slightly lower scores. These findings may serve to better inform evidence-based clinical, research, and policy decision-making.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Predictors and Characteristics of Opioid Utilization >15 Days Following Total Knee Arthroplasty

BACKGROUND

America is amid an opioid epidemic, best characterized by liberal prescribing practices; widespread opioid misuse, abuse, and diversion; and rising rates of prescription-related opioid overdose. While many contributors to opioid overprescribing exist, orthopedic surgery is identified as a key driver. The purpose of this study is to determine predictors of ongoing opioid use >15 days post-total knee arthroplasty (TKA) and those patients prescribed >1350 morphine milligram equivalents (MMEs) in the 15 days following surgery.

METHODS

A retrospective cohort study was conducted in patients undergoing TKA (January 2016-December 2017) in an integrated healthcare system. Outcomes of interest were patient and clinical characteristics.

RESULTS

A total of 621 patients were included in the study. The majority were female (57.6%), were non-Hispanic/Latino white (92.3%), and from metropolitan areas (64.3%) with fewer than 110,000 population. Mean age was 66.3. Being female (odds ratio [OR] = 1.547, P = .092), having a higher body mass index (OR = 1.043, P = .036), and receipt of more postdischarge prescriptions in the 60-day follow-up period (OR = 8.815, P < .0001) were associated with a greater likelihood of receipt of opioid prescriptions for more than 15 days. Older patients (OR = 0.954, P = .01) and those discharged to home (OR = 0.478, P = .045) were less likely to receive >1350 MME; longer length of stay (OR = 1.447, P = .013) was more likely in those prescribed >1350 MMEs.

CONCLUSION

Several predictors were associated with longer duration and higher doses of opioid prescriptions post-TKA. Further research is needed to ascertain the challenges of opioid prescribing from both the metropolitan surgical team and rural healthcare provider perspective.

Bariatric Surgery Prior to Total Hip Arthroplasty Is Cost-Effective in Morbidly Obese Patients

BACKGROUND

The cost-effectiveness of bariatric surgery to achieve weight loss prior to total hip arthroplasty (THA), and decrease the complications and costs associated with THA in the morbidly obese, is unknown. This study evaluated the cost-effectiveness of bariatric surgery prior to THA for morbidly obese patients with end-stage hip osteoarthritis (OA).

METHODS

A state-transition Markov model was constructed to compare the cost-utility of 2 treatment protocols for patients with morbid obesity and end-stage hip OA: (1) immediate THA and (2) bariatric surgery 2 years prior to THA (combined protocol). The analysis was performed from both a payer and a societal perspective using direct and indirect costs over a 40-year time horizon. Utilities, associated costs, and probabilities for health state transitions were derived from the literature. One-way, 2-way and probabilistic sensitivity analyses were performed to validate the robustness of the base case results, using the standard willingness-to-pay threshold of $100,000/quality-adjusted life years.

RESULTS

From the societal perspective, the combined protocol was more effective (13.16 vs 12.26) with less cost ($91,717 vs $92,684) and thus was the dominant strategy over immediate THA. These results were stable across broad ranges for independent model variables. Monte Carlo simulation with 100,000 samples demonstrated that bariatric surgery prior to THA was the preferred cost-effective strategy over 95% of the time from both a societal and payer perspective.

CONCLUSION

In the morbidly obese patient with end-stage hip OA, bariatric surgery prior to THA is a cost-effective strategy for improving quality of life and decreasing societal and payer costs.

LEVEL OF EVIDENCE

II.

Greater risks of complications, infections, and revisions in the obese versus non-obese total hip arthroplasty population of 2,190,824 patients: a meta-analysis and systematic review

BACKGROUND

Obesity is an epidemic, especially in developed countries. This affects the general health of these patients, especially when they are having a major surgical procedure such as total hip arthroplasty (THA). Several articles have described the effects of obesity on THA with varying conclusions. This meta-analysis aims to compare the outcomes, complications, and peri-operative parameters of THA in the obese (BMI≥30 kg/m²) vs non-obese (BMI<30 kg/m²) population as well as a subgroup analysis of morbidly obese (BMI≥40 kg/m²) vs non-obese population.

METHODS

A multi-database search was performed according to PRISMA guidelines. Data from studies assessing the outcomes and complications of THA in the obese and non-obese population were extracted and analyzed.

RESULTS

Sixty-seven studies were included in this meta-analysis, consisting of 581,012 obese and 1,609,812 non-obese patients. Meta-analysis could not be performed on patient reported outcome measures due to heterogeneous reporting methods. Obese patients had a higher risk of all complications (OR = 1.53, 95%CI: 1.30-1.80, P < 0.001), deep infections (OR = 2.71, 95%CI: 2.08-3.53, P < 0.001), superficial infections (OR = 1.99, 95%CI: 1.55-2.55, P < 0.001), dislocations (OR = 1.72, 95%CI: 1.66-1.79, P < 0.001), reoperations (OR = 1.61, 95%CI: 1.40-1.85, P < 0.001), revisions (OR = 1.44, 95%CI: 1.32-1.57, P < 0.001), and readmissions (OR = 1.37, 95%CI: 1.15-1.63, P < 0.001). When sub-group analysis of morbidly obese (BMI≥40 kg/m²) patients was performed, the risks of all these parameters were even greater.

CONCLUSION

Obese and morbidly obese patients are at higher risks of complications post THA than non-obese patients. Surgeons should be aware of these risks in order to counsel patients and adopt prophylactic strategies to reduce these risks where applicable.

Mental Health and Tobacco Use Are Correlated With Physical Function Outcomes in Patients With Knee Pain and Injury

PURPOSE

To examine the relation between the Patient-Reported Outcomes Measurement Information System (PROMIS) domains of Pain Interference (PROMIS-PI), Depression (PROMIS-D), and Physical Function (PROMIS-PF) for nonoperative patients presenting to our ambulatory sports orthopaedic clinic with knee complaints and to determine whether patient demographic characteristics influence PROMIS scores, particularly tobacco use.

METHODS

All patients treated nonoperatively for a primary complaint of knee pain were recruited for participation. Patients were included if they completed all 3 PROMIS questionnaires prior to their clinical evaluation. Patients were excluded if their treatment plan determined that surgical intervention was warranted. Survey results were compiled, and statistical correlations were run between PROMIS domains and patient demographic characteristics.

RESULTS

A total of 527 PROMIS questionnaire sets were included. PROMIS-PF had a strong negative correlation with PROMIS-PI (R = -0.75, P < .001) and a nearly moderate negative correlation with PROMIS-D (R = -0.47, P < .001). When evaluating patient demographic characteristics, we found a significant decrease in physical function scores and increases in pain and depression scores in both current and former tobacco users compared with nonsmokers. Differences in all PROMIS domains between smokers and nonsmokers exceeded minimal clinically important differences.

CONCLUSIONS

Our study showed an inverse correlation between PROMIS-PI and PROMIS-PF, as well as between PROMIS-D and PROMIS-PI, in patients seen in the ambulatory setting for knee complaints treated nonoperatively. A positive correlation was found between PROMIS-PI and PROMIS-D. Tobacco use was a patient demographic factor found to significantly impact PROMIS scores leading to minimal clinically important differences across all 3 PROMIS domains. The findings of this study may be used to identify patients at high risk of poor outcomes.

LEVEL OF EVIDENCE

Level III, observational study.

Exploring the relationship between body mass index, mental health and outcomes of a regional physiotherapy-led post-arthroplasty review clinic

OBJECTIVE

To determine whether 12-month hip and knee outcomes of a regional arthroplasty clinic were comparable to results from metropolitan-based clinics, and to explore a possible relationship between body mass index and depression to identify groups at risk of not achieving optimal outcomes.

DESIGN

A prospective observational study.

SETTING

A regional physiotherapy-led post-arthroplasty review clinic.

PARTICIPANTS

Patients after hip or knee replacement.

INTERVENTIONS

Patients underwent either total hip or total knee joint arthroplasty.

MAIN OUTCOME MEASURES

SF-12 Health Survey, Oxford Hip/Knee Scale, 10-minute walk test, knee range of motion, body mass index and the Hospital Anxiety and Depression Scale.

RESULTS

Physical outcomes were comparable to those reported by metropolitan-based clinics. People with a high body mass index showed most improvement in the severity of depression compared to those with a lower body mass index.

CONCLUSION

It is important to consider the long-term effects of obesity on arthroplasty outcomes.

Musculoskeletal Symptomatic Areas After Total Knee Replacement for Osteoarthritis

Objective

The objective of this study was to measure cumulative incidence and incidence rate and identify factors associated with new musculoskeletal (MSK) symptomatic areas after total knee replacement (TKR) for osteoarthritis (OA).

Methods

Using data from a randomized controlled trial of patients undergoing elective TKR for OA, we assessed for MSK symptomatic areas by region (neck, hands/wrists/arms/shoulders, back, hips, nonindex knee, and ankles/feet) at baseline (pre‐TKR), and at 3, 6, 12, 24, 36, and 48 months post‐TKR. Cumulative incidence and incidence rates were calculated for each region. Factors associated with incident MSK symptomatic areas were identified using generalized linear mixed models. Time to incident symptomatic area was assessed using Cox proportional hazards regression.

Results

Among 293 subjects, the cumulative incidence of any new MSK symptomatic area over 4 years was 45%; the incidence rate was 19.2 per 100 person‐years. Body site–specific cumulative incidence and incidence rates were highest for nonindex knee and back. Predictors of incident MSK symptomatic areas included female sex (relative risk [RR] 1.64; 95% confidence interval [CI] 1.15‐2.34), body mass index of 35 or higher (RR 1.27; 95% CI 0.88‐1.85), Charlson Comorbidity Index 2 or more (RR 1.28; 95% CI 0.92‐1.78), baseline index knee Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score greater than 40 (RR 1.39; 95% CI 0.99‐1.95), and anxiety/depression (measured by the five‐item Mental Health Index) (RR 1.70; 95% CI 1.20‐2.40).

Conclusion

Incident MSK symptomatic areas occurred in roughly half of recipients of TKR in the 4 years after the operation. Further study is needed to examine the long‐term impact of MSK symptomatic areas on postoperative pain, function, and quality of life.

Metformin protects bone mass in ultra-high-molecular-weight polyethylene particle-induced osteolysis by regulating osteocyte secretion

Metformin, an anti-hyperglycemic agent used for type 2 diabetes, has recently been found to have more effects apart from glucose regulation. We found that, in ultra-high-molecular-weight polyethylene particle-induced osteolysis mouse models, metformin had bone protect property and reduced the negative regulator of bone formation sclerostin (SOST) and Dickkopf-related protein 1 (DKK1), and increased osteoprotegerin (OPG) secretion and the ratio of OPG/Receptor Activator for Nuclear Factor-κB Ligand (RANKL). In vitro, we established a 3D co-culture system in which metformin affects osteoblasts and osteoclasts through mature osteocytes secretion. Metformin (50 μM) significantly decreased SOST and DKK1 mRNA expression, stimulating alkaline phosphatase activity and proliferation of osteoblast, and increased OPG secretion and the ratio of OPG/RANKL, inhibiting osteoclastogenesis. Moreover, the effect on OPG was reversed by adenosine 5'-monophosphate-activated protein kinase inhibitor, Compound C. Our finding suggests that metformin induces differentiation and mineralization of osteoblasts, while inhibits osteoclastogenesis via mature osteocytes secretion. Therefore, the drug might be beneficial for not only diabetes but also in other bone disorders by acting on mature osteocytes.

Bariatric Surgery Improves Outcomes After Lower Extremity Arthroplasty in the Morbidly Obese: A Propensity Score-Matched Analysis of a New York Statewide Database

BACKGROUND

The purpose of this study was to compare risks for revision and short-term complications after total joint arthroplasty (TJA) in matched cohorts of morbidly obese patients, receiving and not receiving prior bariatric surgery.

METHODS

Patients undergoing elective TJA between 1997 and 2011 were identified in a New York Statewide database, analyzing total knee arthroplasty (TKA) and total hip arthroplasty (THA) separately. Propensity scores were used to match morbidly obese patients receiving and not receiving bariatric surgery prior to TJA. Cox proportional hazard modeling assessed revision risk. Logistic regression evaluated odds for complications.

RESULTS

For TKA, 2636 bariatric surgery patients were matched to 2636 morbidly obese patients. For THA, 792 bariatric surgery patients were matched to 792 morbidly obese patients. Matching balanced all covariates. Bariatric surgery reduced co-morbidities prior to TJA (TKA P < .0001; THA P < .005). Risks for in-hospital complications were lower for THA and TKA patients receiving prior bariatric surgery (odds ratio [OR] 0.25, P < .001; and OR = 0.69, P = .021, respectively). Risks for 90-day complications were lower for TKA (OR 0.61, P = .002). Revision risks were not different for either THA (P = .634) or TKA (P = .431), nor was THA dislocation risk (P = 1.000).

CONCLUSION

After accounting for relevant selection biases, bariatric surgery prior to TJA was associated with reduced co-morbidity burden at the time of TJA and with reduced post-TJA complications. However, bariatric surgery did not reduce the risk for revision surgery for either TKA or THA.

General and Abdominal Obesity as Risk Factors for Late-Life Mobility Limitation After Total Knee or Hip Replacement for Osteoarthritis Among Women

OBJECTIVE

To investigate associations of body mass index (BMI), waist circumference (WC), and waist/hip ratio (WHR) with survival to age 85 years with mobility limitation or death before age 85 years among older women with total knee replacement (TKR) or total hip replacement (THR) for osteoarthritis (OA).

METHODS

This was a prospective study of women (ages 65-79 years at baseline) from the Women's Health Initiative, recruited during 1993-1998 and followed through 2012. Women's Health Initiative data were linked to Medicare claims data to determine TKR (n = 1,867) and THR (n = 944) for OA. Women were followed for up to 18 years after undergoing THR or TKR to determine mobility status at age 85 years.

RESULTS

Compared with normal-weight women, overweight, obese I, and obese II women with THR had significantly increased risk of survival to age 85 years with mobility limitation (P < 0.001 for linear trend), with the strongest risk among obese II women (odds ratio [OR] 4.37 [95% confidence interval (95% CI) 1.96-9.74]). Obese II women with THR also had increased risk of death before age 85 years. Women with THR and WC >88 cm relative to ≤88 cm had increased risk of survival to age 85 years with mobility limitation (OR 1.65 [95% CI 1.17-2.33]) but not death before age 85 years. High BMI, WC, and WHR were associated with significantly increased risk of late-life mobility limitation and death among women with TKR for OA.

CONCLUSION

Among older women who underwent THR or TKR for OA, baseline general and abdominal obesity were associated with increased risk of late-life mobility limitation.

Re-admissions treble the risk of late mortality after primary total hip arthroplasty

BACKGROUND

Following a total hip arthroplasty (THA), early hospital re-admission rates of 3-11% are considered as 'acceptable' in terms of medical care cost policies. Surprisingly, the impact of re-admissions on mortality has not been priorly portrayed. Therefore, we sought to determine the mortality rate after 90-day re-admissions following a THA in a series of patients from a captive medical care program.

PATIENTS AND METHODS

We prospectively analysed 90-day readmissions of 815 unilateral, elective THA patients operated upon between 2010 and 2014 whose medical care was the one offered by our institution. We stratified our sample into readmitted and non-readmitted cohorts. Through a Cox proportional hazards model, we compared demographic characteristics, clinical comorbidities, surgical outcomes and laboratory values between both groups in order to determine association with early and late mortality.

RESULTS

We found 37 (4.53%) re-admissions at a median time of 40.44 days (IQR 17.46-60.69). Factors associated with re-admission were hospital stay (p = 0.00); surgical time (p = 0.01); chronic renal insufficiency (p = 0.03); ASA class 4 (p = 0.00); morbid obesity (p = 0.006); diabetes (p = 0.04) and a high Charlson index (p = 0.00). Overall mortality rate of the series was 3.31% (27/815). Median time to mortality was 455.5 days (IQR 297.58-1170.65). One-third (11/37) of the re-admitted patients died, being sepsis non-related to the THA the most common cause of death. After adjusting for confounders, 90-day re-admissions remained associated with mortality with an adjusted HR of 3.14 (CI95% 1.05-9.36, p = 0.04).

CONCLUSIONS

Unplanned re-admissions were an independent risk factor for future mortality, increasing three times the risk of mortality.

The Feasibility of Community-Based, Supervised Exercise Programs to Engage and Monitor Patients in a Postrehabilitation Setting

Objective. To evaluate the feasibility of disease-specific, community-based supervised exercise programs (CSEPs) to improve biometric and functional outcomes among persons with a variety of chronic medical conditions. Design. Feasibility, cohort study. Subjects were recruited through community placed flyers and provider offices. Exercise programs consisted of aerobic and resistance training that adhered to American College of Sports Medicine guidelines. A Wilcoxon signed rank test was used to assess program outcomes. Setting. Ten, community-based, medical fitness centers. Subjects. A total of 382 total participants. The number of participants in each CSEP ranged from 38 to 119. Individuals were 18 years of age or older and treated for various chronic medical conditions. Results. Varied by cohort, but generally consisted of (a) favorable changes in body composition ( P < .05), (b) significant improvements in submaximal exercise tolerance and functional outcome measures ( P < .05), and (3) significant increase in self-reported exercise behaviors ( P < .05). Conclusion. CSEPs improve outcomes in patients with chronic medical conditions and may be relevant within the continuum of care in outpatient rehabilitation medicine, particularly among bundled or value-based payment models. Further research is needed to evaluate outcomes from CSEPs versus controls.

Can bariatric surgery delay the need for knee replacement in morbidly obese osteoarthritis patients

Objective:

The objective of the study was to find the weight reduction pattern and its outcome on knee pain and function in osteoarthritis (OA) morbidly obese patients’ post-bariatric surgery with dietary and exercise changes.

Methodology:

Thirty morbidly obese (body mass index [BMI] >40 kg/m²) OA patients gave consent for bariatric surgery. Despite wearisome lifestyle modifications for weight loss and knee pain, satisfactory results were not retrieved. We took consent from all the patients predetermined for knee replacement in future because of pain and disability as recommended by knee replacement surgeon. The dietary and exercise protocol was standardised for all patients for bariatrics. Data for weight loss, change in BMI and Western Ontario and McMaster Universities Arthritis Index score consisting of pain, stiffness and activities of daily livings (ADLs) scores were documented at baseline, 3 months and 6 months post-bariatric surgery.

Results

The male-to-female ratio was 1:2. Mean age of the patients was 49.8 ± 8.6 years. Significant changes in pain (P < 0.001), stiffness (P < 0.001) and ADLs (P < 0.001) were found postoperatively at 3 and 6 months. Positive correlation of percentage change of BMI was seen with percentage change in pain (r = 0.479, P = 0.007) and ADLs (r = 0.414, P = 0.023) after 6 months of bariatric surgery. Most of the patients were inclined to delay the knee replacement further by the end of 6 months post-bariatric surgery.

Conclusion:

Bariatric surgery when combined with dietary and exercise changes gave significant results in terms of weight loss, knee pain and function. It is an approach that tackles both obesity and OA. It is a major step forward in stemming the global epidemic of these two interlinked conditions.

Effect of Obesity on Pain and Functional Recovery Following Total Knee Arthroplasty

BACKGROUND

While obesity may be a risk factor for complications following total knee arthroplasty, data remain sparse on the impact of the degree of obesity on patient-reported outcomes following this procedure. Our objective was to determine the extent to which obesity level affects the trajectory of recovery as well as patient-reported pain, function, and satisfaction with surgery following total knee arthroplasty.

METHODS

We followed a cohort of patients who underwent total knee arthroplasty at 1 of 4 medical centers. Patients were ≥40 years of age with a primary diagnosis of osteoarthritis. We stratified patients into 5 groups according to the World Health Organization classification of body mass index (BMI). We assessed the association between BMI group and pain and function over the time intervals of 0 to 3, 3 to 6, and 6 to 24 months using a piecewise linear model. We also assessed the association between BMI group and patient-reported outcomes at 24 months. Multivariable models adjusted for age, sex, race, diabetes, musculoskeletal functional limitations index, pain medication use, and study site.

RESULTS

Of the 633 participants included in our analysis, 19% were normal weight (BMI of <25 kg/m), 32% were overweight (BMI of 25 to 29.9 kg/m), 27% were class-I obese (BMI of 30 to 34.9 kg/m), 12% were class-II obese (BMI of 35 to 39.9 kg/m), and 9% were class-III obese (BMI of ≥40 kg/m). Study participants with a higher BMI had worse preoperative WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) pain and function scores and had greater improvement from baseline to 3 months. The mean change in pain and function from 3 to 6 and from 6 to 24 months was similar across all BMI groups. At 24 months, participants in all BMI groups had similar levels of pain, function, and satisfaction.

CONCLUSIONS

Because of the differential trajectory of recovery in the first 3 months following total knee arthroplasty, the participants in the higher BMI groups were able to attain absolute pain and function scores similar to those in the nonobese and class-I obese groups. These data can help surgeons discuss expectations of pain relief and functional improvement with total knee arthroplasty candidates with higher BMI.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Morbid Obesity in Total Knee Arthroplasty: Joint-Specific Variance in Outcomes for Operative Time, Length of Stay, and Readmission

BACKGROUND

It is increasingly apparent that the effect of obesity in arthroplasty is joint-specific. This study evaluates the effects of morbid obesity on primary total knee arthroplasty by comparing short-term outcomes between a morbidly obese (body mass index ≥40 kg/m²) and a normal weight (body mass index 18.5-<25 kg/m²) cohort at our institution between January 2003 and December 2010.

METHODS

One hundred seventeen morbidly obese patients were compared with 94 normal weight patients. Operative time, length of stay, complications, 30-day readmission, and readmission length were compared.

RESULTS

Morbid obesity conveyed no significant increase in 30-day readmission. Operative time was increased at 100 minutes in the morbidly obese group, compared with 90.5 minutes (P = .026).

CONCLUSION

Morbid obesity conveyed no increased risk of length of stay or readmission in this cohort.

Influence of Body Mass Index on Sagittal Knee Range of Motion and Gait Speed Recovery 1-Year After Total Knee Arthroplasty

BACKGROUND

The purpose of this prospective study was to investigate the influence of body mass index (BMI) on gait parameters preoperatively and 1 year after total knee arthroplasty (TKA).

METHODS

Seventy-nine patients were evaluated before and 1 year after TKA using clinical gait analysis. The gait velocity, the knee range of motion (ROM) during gait, their gains (difference between baseline and 1 year after TKA), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), quality of life, and patient satisfaction were assessed. Nonobese (BMI <30 kg/m²) and obese patients (BMI ≥30 kg/m²) were compared. Healthy controls were also assessed. Univariate and multivariate linear regression analyses were used to assess the association between gait speed and ROM gains. Adjustment was performed for gender, age, and WOMAC pain improvement.

RESULTS

At baseline, gait velocity and knee ROM were significantly lower in obese compared with those in the nonobese patients (0.99 ± 0.27 m/s vs 1.11 ± 0.18 m/s; effect size, 0.53; P = .021; and ROM, 41.33° ± 9.6° vs 46.05° ± 8.39°; effect size, 0.52; P = .022). Univariate and multivariate linear regressions did not show any significant relation between gait speed gain or knee ROM gain and BMI. At baseline, obese patients were more symptomatic than nonobese (WOMAC pain: 36.1 ± 14.0 vs 50.4 ± 16.9; effect size, 0.9; P < .001), and their improvement was significantly higher (WOMAC pain gain, 44.5 vs 32.3; effect size, 0.59; P = .011).

CONCLUSION

These findings show that all patients improved biomechanically and clinically, regardless of their BMI.

The Influence of Muscle Weakness on the Association Between Obesity and Inpatient Recovery From Total Hip Arthroplasty

BACKGROUND

There is ongoing discussion about whether preoperative obesity is negatively associated with inpatient outcomes of total hip arthroplasty (THA). The aim was to investigate the interaction between obesity and muscle strength and the association with postoperative inpatient recovery after THA.

METHODS

Preoperative obesity (body mass index [BMI] >30 kg/m²) and muscle weakness (hand grip strength <20 kg for woman and <30 kg for men) were measured about 6 weeks before THA. Patients with a BMI <18.5 kg/m² were excluded. Outcomes were delayed inpatient recovery of activities (>2 days to reach independence of walking) and prolonged length of hospital stay (LOS, >4 days and/or discharge to extended rehabilitation). Univariate and multivariable regression analyses with the independent variables muscle weakness and obesity, and the interaction between obesity and muscle weakness, were performed and corrected for possible confounders.

RESULTS

Two hundred and ninety-seven patients were included, 54 (18%) of whom were obese and 21 (7%) who also had muscle weakness. Obesity was not significantly associated with prolonged LOS (odds ratio [OR] 1.36, 95% confidence interval [CI] 0.75-2.47) or prolonged recovery of activities (OR 1.77, 95% CI 0.98-3.22), but the combination of obesity and weakness was significantly associated with prolonged LOS (OR 3.59, 95% CI 1.09-11.89) and prolonged recovery of activities (OR 6.21, 95% CI 1.64-23.65).

CONCLUSION

Obesity is associated with inpatient recovery after THA only in patients with muscle weakness. The results of this study suggest that we should measure muscle strength in addition to BMI (or body composition) to identify patients at risk of prolonged LOS.

Predictive Factors of "Forgotten Knee" Acquisition After Total Knee Arthroplasty: Long-Term Follow-Up of a Large Prospective Cohort

BACKGROUND

In a large prospective cohort, we recently showed that only 66.1% of total knee arthroplasty (TKA) with a perfect outcome according to Knee Society Knee Score was completely forgotten in all everyday activities. The main objective of this study was to identify clinical and orthopedic factors associated with the acquisition of "forgotten knee" (FK).

METHODS

Patients undergoing TKA were enrolled between January 2001 and January 2008. Preoperative medical history, anthropometric data, and clinical data were recorded, and composite scores (Knee Society Score, Lequesne) were assessed. Radiography was performed before and after surgery. At each follow-up, FK acquisition was assessed by a closed question "Does the operated knee feel always normal in all everyday activities?"

RESULTS

We included 510 TKAs performed in 423 patients followed up for a mean of 76.6 ± 28.5 months. On multivariate analysis, depression at baseline and presence of patellar subluxation after surgery were negatively associated with FK acquisition (odds ratio [OR] = 0.28 [95% confidence interval {CI}, 0.13-0.61], P = .001; and OR = 0.31 [0.12-0.79], P = .01, respectively), whereas increased active flexion at last follow-up was positively associated (OR = 1.07 [1.03-1.10], P < .0001). In patients with a perfect outcome (Knee Society Knee Score = 100), preoperative patellar pain, and postoperative patellar subluxation were negatively associated with FK acquisition (OR = 0.41 [0.18-0.93], P = .03 and OR = 0.21 [0.05-0.90], P = .04, respectively). Gender, age, body mass index, preoperative pain and functional limitation, and patellar resurfacing were not significantly related to FK.

CONCLUSION

Depression and patella maltracking may be associated with lack of FK acquisition after TKA, while postoperative increase in flexion may have a positive impact.

Predictors of physical functioning after total hip arthroplasty: a systematic review

OBJECTIVE

The objective of this systematic review of the literature was to identify the predictors of functional outcome after total hip arthroplasty (THA).

METHOD

A systematic literature search in Web of Science, CINAHL, EMBASE and PubMed was conducted on 23 June 2015. The articles were selected based on their quality, relevance and measurement of the predictive factor. The level of evidence of all studies was determined using the GRADE rating scheme.

RESULTS

The initial search resulted in 1092 citations. After application of the inclusion and exclusion criteria, 33 articles met our eligibility criteria and were graded. Included studies were classified as level of evidence low (11), moderate (17) or high (5). Of the included studies, 18 evaluated body mass index (BMI), 17 evaluated preoperative physical functions, 15 evaluated age, 15 evaluated gender and 13 evaluated comorbidity. There was strong evidence suggesting an association between BMI, age, comorbidity, preoperative physical functions and mental health with functional outcome after THA. There was weak evidence suggesting an association between quadriceps strength and education with functional outcome after THA. The evidence was inconsistent for associations with gender and socioeconomic status and functional outcome following THA. We found limited evidence suggesting that alcohol consumption, vitamin D insufficiency and allergies were predictors of functional outcome following THA.

CONCLUSIONS

We have identified multiple predictors of functional outcome after THA, which will enable general practitioners and orthopaedic surgeons to better predict the improvement in physical functioning for their patients with THA. They can use this information to provide patient-specific advice regarding the referral for THA and the expected outcomes after THA. Further research with consistent measurement tools, outcomes and duration of follow-up across studies is needed to confirm the influence of these factors.

Improving patients’ experience and outcome of total joint replacement: the RESTORE programme

Background

Total hip replacements (THRs) and total knee replacements (TKRs) are common elective procedures. In the REsearch STudies into the ORthopaedic Experience (RESTORE) programme, we explored the care and experiences of patients with osteoarthritis after being listed for THR and TKR up to the time when an optimal outcome should be expected.

Objective

To undertake a programme of research studies to work towards improving patient outcomes after THR and TKR.

Methods

We used methodologies appropriate to research questions: systematic reviews, qualitative studies, randomised controlled trials (RCTs), feasibility studies, cohort studies and a survey. Research was supported by patient and public involvement.

Results

Systematic review of longitudinal studies showed that moderate to severe long-term pain affects about 7–23% of patients after THR and 10–34% after TKR. In our cohort study, 10% of patients with hip replacement and 30% with knee replacement showed no clinically or statistically significant functional improvement. In our review of pain assessment few research studies used measures to capture the incidence, character and impact of long-term pain. Qualitative studies highlighted the importance of support by health and social professionals for patients at different stages of the joint replacement pathway. Our review of longitudinal studies suggested that patients with poorer psychological health, physical function or pain before surgery had poorer long-term outcomes and may benefit from pre-surgical interventions. However, uptake of a pre-operative pain management intervention was low. Although evidence relating to patient outcomes was limited, comorbidities are common and may lead to an increased risk of adverse events, suggesting the possible value of optimising pre-operative management. The evidence base on clinical effectiveness of pre-surgical interventions, occupational therapy and physiotherapy-based rehabilitation relied on small RCTs but suggested short-term benefit. Our feasibility studies showed that definitive trials of occupational therapy before surgery and post-discharge group-based physiotherapy exercise are feasible and acceptable to patients. Randomised trial results and systematic review suggest that patients with THR should receive local anaesthetic infiltration for the management of long-term pain, but in patients receiving TKR it may not provide additional benefit to femoral nerve block. From a NHS and Personal Social Services perspective, local anaesthetic infiltration was a cost-effective treatment in primary THR. In qualitative interviews, patients and health-care professionals recognised the importance of participating in the RCTs. To support future interventions and their evaluation, we conducted a study comparing outcome measures and analysed the RCTs as cohort studies. Analyses highlighted the importance of different methods in treating and assessing hip and knee osteoarthritis. There was an inverse association between radiographic severity of osteoarthritis and pain and function in patients waiting for TKR but no association in THR. Different pain characteristics predicted long-term pain in THR and TKR. Outcomes after joint replacement should be assessed with a patient-reported outcome and a functional test.

Conclusions

The RESTORE programme provides important information to guide the development of interventions to improve long-term outcomes for patients with osteoarthritis receiving THR and TKR. Issues relating to their evaluation and the assessment of patient outcomes are highlighted. Potential interventions at key times in the patient pathway were identified and deserve further study, ultimately in the context of a complex intervention.

Study registration

Current Controlled Trials ISRCTN52305381.

Funding

This project was funded by the NIHR Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 4, No. 12. See the NIHR Journals Library website for further project information.

Effect of body mass index on knee function outcomes following continuous passive motion in patients with osteoarthritis after total knee replacement: a retrospective study

OBJECTIVE

Obesity may influence postoperative rehabilitation outcomes after total knee replacement (TKR). The aim of this study was to evaluate the effects of body mass index (BMI) on the progression of inpatient rehabilitation using continuous passive motion (CPM) and its treatment outcomes.

PARTICIPANTS AND SETTING

A retrospective study was conducted in a rehabilitation centre. In total, 354 patients undergoing primary TKR were enrolled through medical chart review.

INTERVENTION

All patients commenced the CPM programme immediately after surgery and continued until hospital discharge.

MAIN OUTCOME MEASURES

Knee flexion, pain score, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function score.

DESIGN

Patients were divided into five BMI groups: normal weight (n=59), overweight (n=95), Class I obesity (n=90), Class II obesity (n=82) and Class III obesity (n=28). All outcome measures were recorded at admission; daily during the inpatient stay; at discharge; and at 1-, 3- and 6-month follow-up assessments.

RESULTS

During CPM exercises, obese patients had a smaller initial flexion angle (P<0.001) and a smaller daily increment in the CPM motion arc (P<0.001) compared with patients of normal weight. Severe obesity was associated with poor knee flexion [adjusted odds ratio (aOR) 11.9, 95% confidence interval (CI) 3.49 to 40.94, P<0.001] and WOMAC physical function score (aOR 5.09, 95% CI 1.62 to 16.03, P=0.005) at 6-month follow-up.

CONCLUSIONS

Obesity had a negative effect on progress during the CPM protocol, which commenced immediately after surgery and continued until discharge. Obesity was also associated with poorer self-reported function at 6-month follow-up.

[Total hip arthroplasty in overweight osteoarthritis patients]

BACKGROUND

An increasing number of patients scheduled for total hip arthroplasty (THA) are obese and exhibit a different risk profile from that of patients of normal weight.

OBJECTIVES

To provide an overview of the impact of obesity on the outcome of primary THA.

MATERIALS AND METHODS

Literature review and discussion of own epidemiological data.

RESULTS

Obese patients can expect as much functional improvement as non-obese patients after THA. However, peri- and postoperative complication (e.g., periprosthetic infection and dislocation) rates are reported to be increased in obese THA patients.

CONCLUSIONS

The knowledge of obesity-associated risks is the prerequiste for successful THA in obese patients.

Effect of body mass index on functional outcomes following arthroplasty procedures

AIM: To evaluate the body mass index (BMI) change in arthroplasty patients and its impact on the patients’ functional results.

METHODS: Between October 2010 and May 2013, 606 patients who were operated due to gonarthrosis, coxarthrosis, aseptic loosening of the total knee and hip prosthesis were evaluated prospectively. Patients were operated by three surgeons in three medical centers. Patients who were between 30-90 years of age and who were underwent total knee arthroplasty, total hip arthroplasty, revision knee arthroplasty, or revision hip arthroplasty were included in the study. We excluded the patients who cannot tolerate our standard postoperative rehabilitation program. Additionally, patients who had systemic inflammatory diseases, diabetes mellitus, or endochrinopathies were excluded from the study. The remaining 513 patients comprised our study group. Preoperative functional joint scores, height, weight and BMI of all patients were recorded. We used the Knee Society Score (KSS) for knee and Harris Hip Score (HHS) for hip patients. Postoperative functional scores were measured at 1^st, 6^th and 12^th months and recorded separately at outpatient visits.

RESULTS: The mean age of the patients was 64.7 (range: 30-90) years (207 males/306 females) and the mean follow-up duration was 14.3 (range: 12-26) mo. We found that arthroplasty patients had weight gain and had an increase in BMI at the postoperative 1^st, 6^th and 12^th months. The mean BMI of the patients was 27.7 preoperatively, 27.8 at the postoperative 1^st month, 28.1 at the 6^th month and 28.6 at the 12^th month (P < 0.01). At the last visit, the mean postoperative HHS of the hip arthroplasty patients was 82.2 ± 7.12 (preoperatively, 52.3; 1^st month, 78.2; 6^th month, 81.1; 12^th month, 82.2), and the mean KSS of the knee arthroplasty patients was 79.3 ± 4.31 (preoperatively, 35.8; 1^st month, 75.2; 6^th month, 79.1; 12^th month, 79.3). Worse functional results were noted in the patients who had a BMI increase, however, this correlation was statistically significant only at the postoperative 6^th month (P = 0.03).

CONCLUSION: To prevent the negative functional effects of this weight gain during the postoperative period, arthroplasty patients should be advised for weight control and risky patients should consult with a dietician.

Development of a Prediction Model to Estimate the Risk of Walking Limitations in Patients with Total Knee Arthroplasty

Objective.

Early and accurate risk prediction of walking limitations after total knee arthroplasty (TKA) is important for clinical and economic reasons. However, to our knowledge, no studies have systematically integrated multiple predictors into a single, clinically practical model. Our study aimed to develop a prediction model to estimate the risk of post-TKA walking limitations.

Methods.

We performed a prospective cohort study of 1096 patients who underwent elective, primary TKA between July 2013 and September 2014. Candidate predictors included patient demographics, surgical factors, and pre- and early (1-mo) post-TKA functional measures. The outcome of interest was self-reported walking limitations at 6 months of post-TKA. We used multivariable proportional odds regression with bootstrap internal validation to develop the model.

Results.

In all, 12% of patients reported walking limitations (maximum walk time ≤ 15 min) at 6 months postsurgery. The main predictors of increasing levels of walking limitations were preoperative walking limitations (overall p < 0.001), higher levels of body mass index [interquartile range (IQR)-OR 1.3, 95% CI 1.2–1.5], lower values of 1-month post-TKA gait speed (IQR-OR 1.9, 95% CI 1.3–2.6), the presence of contralateral knee pain (OR 1.9, 95% CI 1.2–3.0), and the use of a quadstick preoperatively (OR 3.5, 95% CI 1.7–7.3). The prediction model had an optimism-corrected concordance index of 0.71.

Conclusion.

A small but sizable proportion of patients with TKA had persistent mobility limitations. Our prediction model may help to risk-stratify patients, and external validation is required before the model can be used in clinical practice.