The Joint Clinic: Managing Excess Demand for Hip and Knee Osteoarthritis Referrals Using a New Physiotherapy-Led Outpatient Service

Background

There are increasing problems with access to both outpatient assessment and joint replacement surgery for patients with hip or knee osteoarthritis.

Five Questions to Identify Patients With Osteoarthritis of the Knee

BackgroundTo treat the increasing number of patients with osteoarthritis (OA) of the knee, high-volume institutions rely on central referral services as first contact point. Depending on the grading of arthritis, patients will be referred to a nonoperative or operative care provider. The present study reports on a simple 5-step questionnaire to identify patients with OA (Kellgren/Lawrence [KL] grade ≥2) of the knee to improve efficiency of referrals.MethodsWe included 998 patients who contacted the physician referral service at the author’s institution complaining of knee pain and divided them into 2 groups. The study group included patients with an appointment and consisted of 646 patients (345 women [53.4%] and 301 men [46.6%]). X-rays of the knee were graded according to the KL classification system. The control group of patients who did not make an appointment consisted of 352 patients (187 women [53.1%] and 165 men [46.9%]). These patients were contacted to evaluate whether they had been diagnosed with OA of the knee since their initial call, to assure that the study group was not exposed to a selection bias.ResultsLogistic regression revealed 5 questions as significant predictors for OA of the knee (KL grade ≥2). When combining both groups, an 86.9% sensitivity, a 73.3% specificity, and an 84.3% overall accuracy were reached, when patients answered 3 or more questions positively.ConclusionThe present study revealed a simple 5-step questionnaire to identify patients with OA of the knee. Implementation of the questionnaire has the potential to improve the accuracy of referral processes and streamline organization before the first appointment.     

Hip and knee joint rotations differ between patients with medial and lateral knee osteoarthritis: gait analysis of 30 patients and 15 controls.

The motions and moments in the hip and knee in female patients on the waiting list for knee prosthesis surgery with medial (n = 15) or lateral (n = 15) osteoarthritis (OA) were compared with a control group (n = 15). We hypothesized that not only the kinematics and kinetics of the knee but also of the hip would differ between patients the medial and lateral groups. At midstance, patients with lateral OA showed slightly (2 degrees) more maximal (peak) adduction (p = 0.015) of the hip joint and patients with medial OA had 7 degrees more abduction (p < 0.001) than did controls. In patients with lateral OA, the femur was positioned in about 7 degrees more maximum external rotation (p = 0.001), but femur position did not differ between medial OA and controls (p > or = 0.8). There was a tendency to higher internal hip rotation moment in lateral OA compared to controls (p = 0.021). The maximum values of the internal knee abduction moments were 52% higher in medial OA (p = 0.005) and 63% lower in lateral OA (p < 0.001) compared to controls. Cases with medial OA had 9 degrees more, whereas those with lateral OA had 6 degrees less external tibial rotation than controls (medial vs. lateral OA, p = 0.001). We found an association between presence of lateral OA of the knee and the biomechanics of the hip joint. It remains to be evaluated if the changed biomechanics of the hip joint is a reason for development of lateral OA or an observation that is a result of this disease.     

Synchronous Periprosthetic Joint Infections: High Mortality,Reinfection, and Reoperation

BackgroundSynchronous periprosthetic joint infections (PJIs) are a catastrophic complication with potentially high mortality. We aimed to report mortality, risk of reinfection, revision, reoperation, and implant survivorship after synchronous PJIs.MethodsWe identified 34 patients treated for PJI in more than one joint within a single 90-day period from 1990 to 2018. PJIs involved bilateral knee arthroplasty (27), bilateral hip arthroplasty (4), 1 knee arthroplasty and 1 elbow arthroplasty (1), 1 knee arthroplasty and 1 shoulder arthroplasty (1), and bilateral hip and knee arthroplasty (1). Irrigation and debridement with component retention was performed in 23 patients, implant resection in 10 patients, and a combination of irrigation and debridement with component retention and implant resection in 1 patient. A competing risk model was used to analyze implant survivorship, and Kaplan-Meier survival was used for patient mortality. Mean follow-up was 6 years.ResultsMortality was high at 18% at 30 days and 27% at 1 year. The 1-year cumulative incidence of any reinfection was 13% and 27% at 5 years. The 1-year cumulative incidence of any revision or implant removal was 6% and 20% at 5 years. The 1-year cumulative incidence of unplanned reoperation was 25% and 35% at 5 years. Rheumatoid arthritis was associated with increased risk of mortality (HR 7, P < .01), as was liver disease (HR 4, P = .02).ConclusionIn the largest series to date, patients with synchronous PJIs had a high 30-day mortality rate of 18%, and one-fourth underwent unplanned reoperation within the first year.     

Return to Work Following Total Knee and Hip Arthroplasty: The Effect of Patient Intent and Preoperative Work Status

BackgroundThe ability of total knee and hip arthroplasty (TKA/THA) to facilitate return to work (RTW) when it is the patient’s preoperative intent to do so remains unclear. We aimed at determining whether TKA/THA facilitated RTW in patients of working age who intended to return.MethodsThis is a prospective cohort study of 173 consecutive patients <65 years of age, undergoing unilateral TKA (n = 82: median age 58; range, 39-65; 36 [43.9%] male) or THA (n = 91: median age 59; range, 34-65; 42 [46.2%] male) during 2018. Oxford knee/hip scores, Oxford-Activity and Participation Questionnaire, and EuroQol-5 dimension (EQ-5D) scores were measured preoperatively and at 1 year when an employment questionnaire was also completed.ResultsOf patients who intended to RTW, 44 of 52 (84.6%) RTW by 1 year following TKA (at mean 14.8 ± 8.4 weeks) and 53 of 60 (88.3%) following THA (at mean 13.6 ± 7.5 weeks). Failure to RTW despite intent was associated with job physicality for TKA (P = .004) and negative preoperative EQ-5D for THA (P = .01). In patients unable to work before surgery due to joint disease, fewer RTW: 4 of 21 (19.0%) after TKA; and 6 of 17 (35.3%) after THA. Preoperative Oxford knee score >18.5 predicted RTW with 74% sensitivity (P < .001); preoperative Oxford hip score >19.5 predicted RTW with 75% sensitivity (P < .001). Preoperative EQ-5D indices were similarly predictive (P < .001).ConclusionIn this United Kingdom study, preoperative intent to RTW was the most powerful predictor of actual RTW following TKA/THA. Where patients intend to RTW following TKA/THA, 85% RTW following TKA and 88% following THA.     

International Organism Profile of Periprosthetic Total Hip and Knee Infections

BackgroundThere is scarce literature describing pathogens responsible for periprosthetic joint infections (PJIs) around the world. Therefore, we sought to describe periprosthetic joint infection causative organisms, rates of resistant organisms, and polymicrobial infections at 7 large institutions located in North/South America and Europe.MethodsWe performed a retrospective study of 654 periprosthetic hip (n = 361) and knee (n = 293) infections (January 2006 to October 2019) identified at Cleveland Clinic Ohio/Florida in the United States (US) (n = 159), Hospital Italiano de Buenos Aires in Argentina (n = 99), Hospital Asociación Española in Uruguay (n = 130), Guy’s and St Thomas’ Hospital in the United Kingdom (UK) (n = 103), HELIOS Klinikum in Germany (n = 59), and Vreden Institute for Orthopedics in St. Petersburg, Russia (n = 104). Analyses were performed for the entire cohort, knees, and hips. Alpha was set at 0.05.ResultsOverall, the most frequent organisms identified were Staphylococcus aureus (24.8%) and Staphylococcus epidermidis (21.7%). The incidence of organisms resistant to at least one antibiotic was 58% and there was a significant difference between hips (62.3%) and knees (52.6%) (P = .014). Rates of resistant organisms among countries were 37.7% (US), 66.7% (Argentina), 71.5% (Uruguay), 40.8% (UK), 62.7% (Germany), and 77.9% (Russia) (P < .001). The overall incidence of polymicrobial infections was 9.3% and the rates across nations were 9.4% in the US, 11.1% in Argentina, 4.6% in Uruguay, 4.9% in UK, 11.9% in Germany, and 16.3% in Russia (P = .026).ConclusionIn the evaluated institutions, S aureus and S epidermidis accounted for almost 50% of all infections. The US and the UK had the lowest incidence of resistant organisms while Germany and Russia had the highest. The UK and Uruguay had the lowest rates of polymicrobial infections.     

The Influence of Radiological Severity and Symptom Duration of Osteoarthritis on Postoperative Outcome After Total Hip Arthroplasty: A Prospective Cohort Study

Background

We aimed to investigate the influence of preoperative radiological severity and symptom duration of hip osteoarthritis (OA) on the postoperative functional outcome, quality of life, as well as abductor muscle strength after total hip arthroplasty (THA).

Effectiveness,Patient Satisfaction,and Cost Reduction of Virtual Joint Replacement Clinic Follow-Up of Hip and Knee Arthroplasty

BackgroundTotal hip and knee arthroplasties are increasingly performed operations, and routine follow-up places huge demands on orthopedic services. This study investigates the effectiveness, patients’ satisfaction, and cost reduction of Virtual Joint Replacement Clinic (VJRC) follow-up of total hip arthroplasty and total knee arthroplasty patients in a university hospital. VJRC is especially valuable when in-person appointments are not advised or feasible such as during the COVID-19 pandemic.MethodsA total of 1749 patients who were invited for VJRC follow-up for knee or hip arthroplasty from January 2017 to December 2018 were included in this retrospective study. Patients were referred to VJRC after their 6-week postoperative review. Routine VJRC postoperative review was undertaken at 1 and 7 years and then 3-yearly thereafter. We evaluated the VJRC patient response rate, acceptability, and outcome. Patient satisfaction was measured in a subgroup of patients using a satisfaction survey. VJRC costs were calculated compared to face-to-face follow-up.ResultsThe VJRC had a 92.05% overall response rate. Only 7.22% required further in-person appointments with only 3% being reviewed by an orthopedic consultant. VJRC resulted in an estimated saving of £42,644 per year at our institution. The patients’ satisfaction survey showed that 89.29% of the patients were either satisfied or very satisfied with VJRC follow-up.ConclusionVJRC follow-up for hip and knee arthroplasty patients is an effective alternative to in-person clinic assessment which is accepted by patients, has high patient satisfaction, and can reduce the cost to both health services and patients.     

Satisfaction With the Process vs Outcome of Care in Total Hip and Knee Arthroplasty

BackgroundPatient satisfaction, with both process of care and outcome of care, is critical for measuring the quality and value of elective procedures such as arthroplasty. The purpose of this study is to evaluate the correlation between early postoperative satisfaction with the process of care and 2-year satisfaction with the outcome of care after total hip arthroplasty (THA) and total knee arthroplasty (TKA).MethodsWe retrospectively analyzed data from institutional arthroplasty registries. Satisfaction with the outcome of care was measured on a scale of 0-100 by a previously validated questionnaire administered 2 years postoperatively. Patient satisfaction with the process of care was measured by the Press Ganey (PG) inpatient survey, also scored 0-100. We examined the correlation between these 2 measures of satisfaction in patients who underwent primary THA or TKA.ResultsIn total, 721 TKA patients and 760 THA patients underwent surgery and completed both the PG survey and 2-year satisfaction questionnaire. The mean age was 65.1 years with a mean body mass index of 28.8 and 56% were female. The mean PG survey score for the entire cohort was 95.6. The mean 2-year satisfaction score was 90.3. The Spearman correlation coefficient between the PG survey and the 2-year satisfaction survey was 0.23 for TKA patients (P < .001) and 0.13 for THA patients (P < .001).ConclusionWe found a weak correlation between the measurement of satisfaction with the process of care surrounding hip and knee arthroplasty using the PG survey and measurement of satisfaction with the outcome of care after arthroplasty using a validated 2-year satisfaction instrument.     

Comparison of Long-Term Survival Analysis Between Open-Wedge High Tibial Osteotomy and Unicompartmental Knee Arthroplasty

BackgroundTo compare unicompartmental knee arthroplasty (UKA) and open-wedge high tibial osteotomy (OWHTO) in a long-term follow-up propensity score matching analysis.MethodsPatients who underwent UKA or OWHTO for unilateral medial unicompartmental osteoarthritis (OA) between 2004 and 2010 were included. The ROM, HSS score, KS score, WOMAC score, forgotten joint score, OA progression in patellofemoral and lateral compartments, and survivorship were compared within ten years of follow-up between 67 UKA and 67 OWHTO patients after propensity score matching for age, gender, body mass index, range of motion, and osteoarthritis (OA) grade.ResultsAt the last follow-up, there were no significant differences between the two groups in clinical outcomes, but the WOMAC score showed better results after UKA (13.1 in UKA vs 18.9 in OWHTO, P = .011). The OA progression also showed no significant difference between the two groups. After a 10-year follow-up, the survival rate was higher in UKA patients (96.2%) than in OWHTO patients (87.7%), with no statistical difference (P = .06).ConclusionUKA showed better clinical outcomes and OA progressions than OWHTO. The survival rate presented a superiority of 8.5% for the UKA group in the 10-year follow-up, without significant difference.     

Abnormal loading of the hip and knee joints in unilateral hip osteoarthritis persists two years after total hip replacement

A total hip replacement (THR) is a common and routine procedure to reduce pain and restore normal activity. Gait analysis can provide insights into functional characteristics and dynamic joint loading situation not identifiable by clinical examination or static radiographic measures. The present prospective longitudinal study tested whether 2 years after surgery a THR would restore dynamic loading of the knee and hip joints in the frontal plane to normal. Instrumented gait analysis was performed shortly before surgery and approximately 2 years after THR on 15 unilateral hip osteoarthritis (OA) patients. 15 asymptomatic matched individuals were recruited as healthy controls. Results showed that abnormal joint loading persisted 2 years after THR. The 2nd external knee adduction moment in terminal stance in the affected (?34%, p = 0.002, d = 1.22) and non‐affected limb (?25%, p = 0.035, d = 0.81) was lower compared to controls and thus indicated a shift in the knee joint load distribution from medial to lateral. A correlation analysis revealed that a smaller hip range of motion explained 46% of 2nd knee adduction moment alterations. In contrast, the 2nd external hip adduction moment in terminal stance was postoperatively higher in the affected (+22%, p = 0.007, d = 1.04) and non‐affected limb (+22%, p = 0.005, d = 1.05). Here, 51% of 2nd hip adduction moment alterations can be explained with a greater hip adduction angle. Patients with a THR may therefore be at higher risk for abnormal joint loading and thus for the development of OA in other joints of the lower extremities. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2167–2177, 2018.

     

Irrigation and Debridement With Implant Retention: Does Chronicity of Symptoms Matter?

BackgroundPeriprosthetic joint infection (PJI) remains a rare, yet devastating complication of total joint arthroplasty (TJA). Chronic infection is generally considered a contraindication to debridement, antibiotics, and implant retention (DAIR); however, outcomes stratified by chronicity have not been well documented.MethodsA retrospective review of all DAIR cases performed at a single institution from 2008 to 2015 was performed. Chronicity of PJI was categorized as acute postoperative, chronic, or acute hematogenous. Failure after DAIR, defined as re-revision for infection recurrence with the same organism, was evaluated between the 3 chronicity groups at 90 days as well as at a minimum 2-year follow-up.ResultsOverall, 248 patients undergoing DAIR for total hip arthroplasty or total knee arthroplasty PJI were included. Categorization of PJI was acute (acute postoperative) in 59 cases (24%), chronic in 54 (22%), and acute hematogenous in 135 (54%). DAIR survivorship was 47% (range 0.3-10 years). Overall, there were 118 (47.6%) treatment failures after DAIR with a minimum of 2-year follow-up. There was no difference in failure rate between total hip or total knee arthroplasty patients (P = .07). Patients infected with Staphylococcus conferred a higher risk of failure for all DAIR procedures regardless of chronicity category.ConclusionIdentification of microbial species prior to undertaking DAIR may be more clinically relevant than stratification according to chronicity category when considering treatment options.     

Unicompartmental Knee Arthroplasty Patients Have Lower Joint Awareness and Higher Function at 5 Years Compared to Total Knee Arthroplasties: A Matched Comparison

BackgroundThe purpose of this study was to evaluate postoperative outcomes at minimum 5-year follow-up in patients following unicompartmental knee arthroplasty (UKA) compared to a matched cohort of total knee arthroplasty (TKA) patients.MethodsPatients who had primarily medial compartment osteoarthritis (OA) who met criteria for medial UKA underwent TKA or medial UKA between 2014 and 2015 at a single institution, matched for age, sex, and body mass index. There were 127 UKAs in 120 patients and 118 TKAs in 116 patients included with minimum 5-year follow-up (range, 6 to 8). Mean age was 69 years (range, 59 to 79) and 71 years (range, 62 to 80) in the UKA and TKA groups, respectively (P = .049).ResultsPatients who underwent UKA had significantly higher mean (±SD) Forgotten Joint Scores (87 ± 20 versus 59 ± 34, P < .001); higher Knee Society Scores (88 ± 14 versus 75 ± 21, P < .001); and lower Numeric Pain Rating Scores (0.8 ± 1.6 versus 1.9 ± 2.2, P < .001). Survivorship free from all-cause revision was 96% (95% CI = 93%-99%) and 99% (95% CI = 97%-100%) at 5 years for TKA and UKA, respectively (P = .52). There were 8 both component revisions in the TKA group within 5 years from the date of surgery and 2 UKA conversions to TKA after 5-year follow-up.ConclusionPatients who have medial compartment OA and underwent UKA had significantly lower joint awareness, decreased pain, improved function, and higher satisfaction compared to matched TKA patients at minimum 5-year follow-up while maintaining excellent survivorship.     

Stainless Steel Femoral Heads Reduce Rate of Revision When Compared to Ion-Implanted Chromium-Cobalt Heads With a Single Cemented Femoral Design: An Analysis of 40,468 Total Hip Replacements From the Australian Orthopedic Association National Joint Replacement Registry

BackgroundIn order to reduce the incidence of total hip joint replacement revision for wear, multiple advanced materials and alloys targeting hip replacement tribology have been introduced. Ion implantation of chromium-cobalt heads is thought to reduce wear due to increased surface hardness and lower friction. These advances in technology result in additional manufacturing costs. However, it is unclear whether these attributes result in a decreased rate of revision for wear and when used with modern highly crosslinked polyethylene (XLPE). The aim of this study is to compare the survivorship of stainless steel and ion-implanted chromium-cobalt femoral heads in order to determine whether ion implantation has a lower risk of revision.MethodsData from the Australian Orthopedic Association National Joint Replacement Registry included all stainless steel and low-friction ion-treated (LFIT) femoral heads used in conjunction with a primary Exeter/Trident hip replacement combination and XLPE liners performed for osteoarthritis. Kaplan-Meier estimates of survivorship were used to describe the time to first revision. Hazard ratios (HRs) from Cox proportional hazard models, with adjustment for age and gender, were used to compare revision rates between the 2 groups.ResultsThere were 40,468 total hip replacements that met the inclusion criteria. Stainless steel heads had a lower revision rate compared to LFIT chromium-cobalt heads (HR 0.87, 95% confidence interval 0.76-1.00, P = .048). The difference in the rate of revision was even greater when 32-mm heads were used (HR 0.72, 95% confidence interval 0.58-0.89, P = .002). There was no difference in revision for loosening between head alloys or when stratified by age.ConclusionGiven the increased costs associated with LFIT implants and the lower rate of revision for stainless steel heads, we recommend the use of a stainless steel heads when using an Exeter/Trident hybrid hip with an XLPE liner.     

More Severe Radiographic Osteoarthritis Is Associated With Increased Improvement in Patients’ Health State Following a Total Knee Arthroplasty

BackgroundTo assess whether preoperative radiological severity of osteoarthritis (OA) is related to the level of improvement in patients’ health state measured 1 year after total knee arthroplasty (TKA).MethodsRadiographic severity of OA was graded using the Kellgren-Lawrence (KL) classification. Two independent observers were blinded to patients’ outcome scores. Health-related quality of life was measured using EQ-5D-3L preoperatively and at 12-month follow-up. The 5 dimensions of the EQ-5D were converted into a health state index score. The association between KL grade and improvement in health state score was analyzed using multiple linear regression.ResultsAmong 156 consecutive patients (68% females, mean age 69 years) who underwent primary TKA, 3 knees (2%) were classified as KL grade 2, 115 as KL grade 3 (74%), and 38 as KL grade 4 (24%). Follow-up rate was 77%. There was substantial intra-rater and inter-rater agreement (Cohen’s kappa = 0.80 and 0.79). Most patients (64%) had clinically significant improvement in their health state score 1 year after TKA. However, after adjusting for relevant covariates, patients with severe OA (KL grade 4) were found to have significantly more improvement in their health state score than patients with mild or moderate OA (KL grade 2 or 3, respectively). Separate analysis of the 5 EQ-5D dimensions showed that the KL group differences were most evident in the “usual activities” and “pain/discomfort” dimensions.ConclusionPatients with severe OA have significantly more improvement in their usual activities and pain/discomfort 1 year after TKA than patients with less severe OA.     

Changes in Patient Reported Outcome Measure Scores From Initial Presentation to Day-of-Surgery in Patients Undergoing Hip and Knee Arthroplasty

BackgroundIt is not well understood how patient reported outcome measures (PROMs) change from initial presentation to day-of-surgery (DOS). This study sought to quantify preoperative PROM changes for hip and knee arthroplasty patients.MethodsA retrospective review was performed on primary total hip, total knee, and partial knee arthroplasty patients from October 2020 through January 2021. Trends in preoperative Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR), and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) scores were compared using scores at initial presentation in the ambulatory clinic and at a time near the date-of-surgery. A total of 497 patients possessed 2 preoperative PROMIS-PF (497/497), HOOS-JR (152/497), or KOOS-JR (258/497) surveys.ResultsThere was no significant statistical difference in mean PROM scores between initial presentation and DOS PROMIS-PF or HOOS-JR scores. Only KOOS-JR demonstrated a significant statistical difference of 2 ± 14 (P = .002) when comparing initial versus preoperative scores. Partial knee arthroplasty patients saw a strong positive correlation (r = 0.77) between initial PROMIS-PF and DOS scores. However, mean absolute value changes on an individual level were 4 ± 4, 11 ± 39, and 11 ± 10 for PROMIS-PF, HOOS-JR, and KOOS-JR, respectively, indicating the presence of meaningful patient-level score changes as based on previously published anchor-based minimal clinically important differences.ConclusionPROMs collected during the preoperative period demonstrated wide variability at an individual level, but not at a population level. Collection at both time points may be necessary in order to understand the clinical impact of surgery on these patients.     

Patients Who Have Limited English Proficiency Have Decreased Utilization of Revision Surgeries After Hip and Knee Arthroplasty

BackgroundWhile racial and ethnic disparities are well documented in access to total joint arthroplasty (TJA), little is known about the association between having limited English proficiency (LEP) and postoperative care access. This study seeks to correlate LEP status with rates of revision surgery after hip and knee arthroplasty.MethodsThis was a retrospective cohort study of patients aged ≥ 18 years who underwent either total hip or total knee arthroplasty between January 2013 and December 2021 at a single academic medical center. The predictor variable was English proficiency status, where LEP was defined as having a primary language that was not English. Multivariable regressions controlling for potential demographic and clinical confounders were used to calculate adjusted odds ratios of undergoing revision surgery within 1 and 2 years after primary arthroplasty for patients who have LEP, compared to English proficient patients.ResultsA total of 7,985 hip and knee arthroplasty surgeries were included in the analysis. There were 577 (7.2%) patients who were classified as having LEP. Patients who have LEP were less likely to undergo revision surgeries within 1 year (1.4% versus 3.2%, P = .01) and 2 years (1.7% versus 3.9%, P = .006) of primary TJA. Patients who have LEP had adjusted odds ratios of 0.45 (confidence interval: 0.22-0.92, P = .03) and 0.44 (confidence interval: 0.23-0.85, P = .01) of receiving revision surgery within 1 and 2 years, respectively.ConclusionPatients who have LEP, compared to English proficient patients, were less likely to undergo revision surgeries at the same institution up to 2 years after hip and knee arthroplasty. These findings suggest that patients who have LEP may face barriers in accessing postoperative care.     

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

BackgroundObesity 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).MethodsA 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.ResultsFor 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.ConclusionThere 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.     

Preoperative Osteoarthritic Grade Affects Forgotten Joint Status and Patient Acceptable Symptom State After Robotic Arm-Assisted Unicompartmental Knee Arthroplasty

BackgroundThis retrospective observational study was designed to investigate the association between radiographic Ahlbäck osteoarthritis (OA) grade and postoperative joint perception in a cohort of patients undergoing medial robotic arm-assisted unicompartmental knee arthroplasty (RA-UKA), using the Forgotten Joint Status and Patient Acceptable Symptom State (PASS) as outcomes.MethodsBetween January 2014 and May 2019, 660 patients (719 knees) underwent medial RA-UKA at 2 centers. Ahlbäck OA grade was measured on preoperative knee radiographs. Postoperatively, patients were administered the Forgotten Joint Score-12 (FJS-12) and 5-level Likert scale to assess patients’ satisfaction. Correlations were described among FJS-12, satisfaction, and Ahlbäck OA grade by means of logistic regression models.ResultsA total of 547 patients (602 knees) were assessed at a mean follow-up of 3.5 years (standard deviation 1.4). A total of 293 cases were graded as Ahlbäck 1 (Group A) and 309 knees were graded as Ahlbäck>1 (Group B). Statistically significant difference was detected in mean FJS-12 (P < .001), but not in the postoperative satisfaction level (P = .06) between the 2 groups. Patients in Group B had a significantly higher probability of attaining a “forgotten knee” after the operation, compared to Group A (P < .05). Cases in Group A had a significantly lower probability of achieving the PASS (P < .01).ConclusionPatients with higher grades of OA (Ahlbäck>1) were more likely to attain a “forgotten knee,” while patients with less severe OA (Ahlbäck 1) were less likely to achieve the PASS after RA-UKA. Although patients with less severe OA reported fairly good outcome, cases in which the results will be poorer are currently difficult to predict.     

Does hip implant positioning affect the peak external adduction moments of the healthy knees of subjects with total hip replacements?

After unilateral total hip replacement (THR) for hip osteoarthritis (OA), knee OA incidence or progression is common. The contralateral knee is at particular risk, and some have speculated that abnormal THR‐hip biomechanics contributes to this asymmetry. We investigated the relationships between operated‐hip joint geometry or gait variables and the peak external knee adduction moments—an indicator of knee OA risk—in 21 subjects with unilateral THRs. We found that the peak adduction moment was 14% higher on the contralateral versus the ipsilateral knee (p = 0.131). The best predictors of ipsilateral knee adduction moments were superior‐inferior joint center position and operated‐hip peak adduction moment (adj R² = 0.291, p = 0.017). The sole predictor of the contralateral knee adduction moment was the medial‐lateral hip center position (adj R² = 0.266, p = 0.010). A postoperative medial shift of the hip center was significantly correlated with a lower postoperative contralateral/ipsilateral knee adduction moment ratio (R = 0.462, p = 0.035). Based on these relationships, we concluded that implant positioning could influence the biomechanical risk of knee OA progression after THR. Although implant positioning decisions are necessarily driven by other factors, it may be appropriate to assess individual THR candidate's knee OA risk and adjust perioperative management accordingly. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1187–1194, 2013