Is Conversion TKA a Primary or Revision? Clinical Course and Complication Risks Approximating Revision TKA Rather Than Primary TKA

BackgroundConversion total knee arthroplasty (convTKA) is associated with increased resource utilization and costs compared with primary TKA. The purpose of this study is to compare 1) surgical time, 2) hospitalization length (LOS), 3) complications, 4) infection, and 5) readmissions in patients undergoing convTKA to both primary TKA and revision TKA patients.MethodsThe American College of Surgeons National Surgical Quality Improvement Project database was queried from 2008 to 2018. Patients undergoing convTKA (n = 1,665, 0.5%) were defined by selecting Current Procedural Terminology codes 27,447 and 20,680. We compared the outcomes of interest to patients undergoing primary TKA (n = 348,624) and to patients undergoing aseptic revision TKA (n = 8213). Univariate and multivariate logistic regression was performed to identify the relative risk of postoperative complications.ResultsCompared with patients undergoing primary TKA, convTKA patients were younger (P < .001), had lower body mass index (P < .001), and were less likely to be American Society of Anesthesiologist class III/IV (P < .001). These patients had significantly longer operative times (122.6 vs 90.3 min, P < .001), increased LOS (P < .001), increased risks for any complication (OR 1.94), surgical site infection (OR 1.84), reoperation (OR 2.18), and readmissions (OR 1.60) after controlling for confounders. Compared with aseptic TKA revisions, operative times were shorter (122.6 vs 148.2 min, P < .001), but LOS (2.91 vs 2.95 days, P = .698) was similar. Furthermore, relative risk for any complication (P = .350), surgical site infection (P = .964), reoperation (P = .296), and readmissions (P = .844) did not differ.ConclusionConversion TKA procedures share more similarities with revision TKA rather than primary TKA procedures. Without a distinct procedural and diagnosis-related group, there are financial disincentives to care for these complex patients.Level of EvidenceII.     

Does Ramosetron Reduce Postoperative Emesis and Pain after TKA?

Background  

Current pain management protocols involving many anesthetic and analgesic drugs reportedly provide adequate analgesia after TKA. However, control of emetic events associated with the drugs used in current multimodal pain management remains challenging.     

Do Patient Race and Sex Change Surgeon Recommendations for TKA?

Background

Prior investigations have suggested that physician-related factors may contribute to differential use of TKA among women and ethnic minorities. We sought to evaluate the effect of surgeon bias on recommendations for TKA.

Questions/purpose

Using an experimental approach with standardized patient scenarios, we sought to evaluate surgeon recommendations regarding TKA, specifically to determine whether recommendations for TKA are influenced by (1) patient race, and (2) patient sex.

Methods

We developed four computerized scenarios for all combinations of race (white or black) and sex (male or female) for otherwise similar patients with end-stage knee osteoarthritis. Patients gave an orthopaedic history of 2 years worsening pain with decreased functional status and failure of oral antiinflammatory medications and corticosteroid intraarticular injections. Orthopaedic surgeons attending the 2012 annual meetings of the New York State Society of Orthopaedic Surgeons and American Association of Hip and Knee Surgeons were recruited for the study. Surgeons passing an open recruitment table at each meeting were asked to participate. Of the 1111 surgeons in attendance at either meeting, 113 (10.2%) participated in the study. All participants viewed the “control” patient’s story (white male) and were randomized to view one of the three “experimental” scenarios (white female, black male, black female). After viewing each scenario, the participants were anonymously asked whether they would recommend TKA. An a priori power analysis showed that 112 participants were needed to detect a 15% difference in the likelihood of recommending surgery for white versus nonwhite patients in the test scenarios evaluated with 90% power at a level of significance of 0.05.

Results

Of the 39 surgeons who viewed the white male plus black female scenario, there were 33 (85%) concordant responses (TKA offered to both patients) and six discordant responses (TKA offered to only one of the patients), with no effect of patient race and sex (p = 0.99). Of the 37 surgeons who viewed the white male plus black male scenario, there were 33 (89%) concordant responses and four discordant responses, with no effect of patient race (p = 0.32). Of the 37 surgeons who viewed the white male plus white female scenario, there were 30 (77%) concordant responses and seven discordant responses, with no effect of patient sex (p = 0.71).

Conclusion

After orthopaedic surgeons viewed video scenarios of patients with end-stage knee osteoarthritis, patient race and sex were not associated with a different likelihood of a surgical recommendation. Our findings support the notion that patient race and sex may be less influential on decision making when there are strong clinical data to support a decision. Physician bias may have a greater effect on decision making in situations where the indications for surgery are less clear.     

What Host Factors Affect Aseptic Loosening After THA and TKA?

Background

Aseptic loosening is the most common cause for revisions after lower-extremity total joint arthroplasties, however studies differ regarding the degree to which host factors influence loosening.

Questions/purpose

We performed a systematic review to determine which host factors play a role in the development of clinical and/or radiographic failure from aseptic loosening after (1) THA and (2) TKA.

Methods

Two searches on THA and TKA, respectively, using four electronic databases (EMBASE, CINAHL Plus, PubMed, and Scopus) were conducted. We identified a total of 209 reports that encompassed nine potential host factors affecting aseptic loosening. Inclusion criteria for consideration of scientific clinical reports were that 20 or more patients were involved, with more than 1-year followup, with at least three studies pertaining to each factor, and at least six of the Methodological Index for Non-randomized Studies criteria met, and with raw data for odds ratio (OR) calculations. Twenty-one studies (16 THA studies with 45,779 hips and five TKA studies with 288 knees, respectively) were used to calculate weighted OR and CIs (using the random effects theory) and study heterogeneity for four different host factors in THAs (male sex, high activity level, obesity defined as BMI ≥ 30 kg/m², and current or former tobacco use) and one factor in TKA (BMI ≥ 30 kg/m²), which were placed in a forest plot.

Results

For THA, male sex (OR, 1.39; 95% CI, 1.22–1.58; p = 0.001) and high activity level (University of California Los Angeles [UCLA] activity score ≥ 8 points; OR, 4.24; 95% CI, 2.46–7.31; p = 0.001) were associated with aseptic loosening. However, obesity (OR, 1.01; 95% CI, 0.73–1.40; p = 0.96), and tobacco use (OR, 1.96; 95% CI, 0.43–8.97; p = 0.39) were not associated with an increased risk of aseptic loosening after THA with the numbers available. For TKA, we found no host factors associated with loosening. In particular, obesity (BMI ≥ 30 kg/m²) was not associated with aseptic loosening with the numbers available (OR, 2.28; 95% CI, 0.60–8.62; p = 0.22).

Conclusions

Patients undergoing a lower-extremity total joint arthroplasty who engage in impact sports should be counseled regarding their potential increased risk of aseptic loosening; however, given the weak evidence available, we believe that higher-level studies are necessary to clearly define the risk factors, particularly with newer-generation constructs.

Level of Evidence

Level IV, therapeutic study.     

复杂膝关节畸形的TKA治疗

目的探讨复杂膝关节畸形行人工全膝关节置换术（TKA）的可行性和手术方法。方法回顾性分析自2000-01—2008-12行TKA的20例（26膝）复杂膝关节畸形伴严重功能障碍患者,经过充分术前准备后,针对不同畸形特点采用不同的截骨矫形方式,并进行相应挛缩软组织松解。内翻畸形以调整胫骨截骨矫正为主,外翻以调整股骨截骨矫正为主,屈曲行调整股骨远端及胫骨后倾截骨,术后加以系统的康复训练。结果本组术后获得1~5年随访,平均矫正内翻畸形15°,外翻畸形10°,屈曲畸形35°。末次随访HSS评分平均（86.5±8.6）分,较术前平均（36.2±15.4）分明显提高,差异有统计学意义（t=-12.812,P〈0.05）。结论复杂膝关节畸形患者行TKA需重视术前评估,并依据膝关节骨质畸形、软组织形成等病理特点,选择针对性的手术方式及系统性的康复训练,最终可获得一个畸形矫正、稳定无痛、功能良好的膝关节。     

Do Surgeon Expectations Predict Clinically Important Improvements in WOMAC Scores After THA and TKA?

Background

Failure of THA or TKA to meet a patient’s expectations may result in patient disappointment and litigation. However, there is little evidence to suggest that surgeons can consistently anticipate which patients will benefit from those interventions.

Questions/purposes

To determine the ability of surgeons to identify, in advance of surgery, patients who will benefit from THA or TKA and those who will not, where ‘benefit’ is defined as a clinically important improvement in a validated patient-reported outcomes score.

Methods

In this prospective study, eight high-volume orthopaedic surgeons completed validated THA and TKA expectations questionnaires (score 0–100, 100 being the highest expectation) as part of preoperative assessment of all their patients scheduled for a THA or TKA and enrolled in the Hospital for Special Surgery institutional registry. Enrolled patients completed the WOMAC preoperatively and at 2 years. Successful outcomes were defined as achieving the minimum clinically important difference (MCID) in WOMAC pain and function subscales. Sensitivity, specificity, and receiver operating characteristic (ROC) curves were used to evaluate the ability of surgeons’ expectation scores to identify patients likely to achieve the MCID on the WOMAC scale. Analyses were run separately for patients having THA and TKA. We enrolled 259 patients undergoing THA and 247 undergoing TKA, of whom 77% (n = 200) and 77% (n = 191) completed followup surveys 2 years after their procedures, respectively.

Results

Surgeons’ expectation scores effectively anticipated patients who would improve after THA, but they were no better than chance in identifying patients who would achieve the MCID on the WOMAC score 2 years after TKA. For patients having THA, the areas under the ROC curve were 0.67 (95% CI, 0.53–0.82; p = 0.02) and 0.74 (95% CI, 0.63–0.85; p < 0.01) for WOMAC function and pain outcomes, respectively, indicating good accuracy. Sensitivity and specificity were maximized on WOMAC pain and function scores (sensitivity = 0.69, specificity = 0.72, both for pain and function) at an expectations score of 83 or greater of 100. Surgeons’ expectations were more accurate for patients who were men, who had a BMI less than 30 kg/m², who had more than one comorbidity, and who were older than 65 years. For patients having TKA, surgeons’ expectation scores were not better than chance for identifying those who would experience a clinically important improvement on the WOMAC scale (area under ROC curve: Function = 0.51, [95% CI, 0.42–0.61], p = 0.78; Pain = 0.51, [95% CI, 0.40–0.61], p = 0.92).

Conclusions

Most patients having THA and TKA achieved the MCID improvement after surgery. However, the inability of surgeons’ expectation scores to discriminate accurately between patients who benefit and those who do not among patients scheduled for THA who are young, with no comorbidities, and with elevated BMIs, and among all patients scheduled for TKA, calls for surgeons to spend more time with these patients to fully understand and address their needs and expectations. Using standardized assessment tools to compare surgeons’ expectations and those of their patients may help focus the surgeon-patient discussion further, and address patients’ expectations more effectively.

Level of Evidence

Level II, therapeutic study.

     

What Are the Frequency,Associated Factors,and Mortality of Amputation and Arthrodesis After a Failed Infected TKA?

Background

For patients with failed surgical treatment of an infected TKA, salvage operations such as arthrodesis or above-knee amputation (AKA) may be considered. Clinical and institutional factors associated with AKA and arthrodesis after a failed TKA have not been investigated in a large-scale population, and the utilization rate and trend of these measures are not well known.

Questions/purposes

(1) How has the frequency of arthrodesis and AKA after infected TKA changed over the last 10 years? (2) What clinical or institutional factors are associated with patients undergoing arthrodesis or AKA? (3) What is the risk of mortality after arthrodesis or AKA?

Methods

The Medicare 100% National Inpatient Claims Database was used to identify 44,466 patients 65 years of age or older who were diagnosed with an infected TKA and who underwent revision between 2005 and 2014 based on International Classification of Diseases, 9^th Revision, Clinical Modification codes. Overall, 1182 knee arthrodeses and 1864 AKAs were identified among the study population. One year of data before the index infection-related knee revision were used to examine patient demographic, institutional, and clinical factors, including comorbidities, hospital volumes, and surgeon volumes. We developed Cox regression models to investigate the risk of arthrodesis, AKA, and death as outcomes. In addition, the year of the index revision was included as a covariate to determine if the risk of subsequent surgical interventions was changing over time. The risk of mortality was also assessed as the event of interest using a similar multivariate Cox model for each patient group (arthrodesis, AKA) in addition to those who underwent additional revisions but who did not undergo either of the salvage procedures.

Results

The number of arthrodesis (hazard ratio [HR], 0.90, p < 0.001) and amputation (HR, 0.95, p < 0.001) procedures showed a declining trend. Clinical factors associated with arthrodesis included acute renal failure (HR, 1.22 [1.06–1.41], p = 0.006), obesity (HR, 1.58 [1.35–1.84], p < 0.001), and having additional infection-related revisions (HR for 2+ additional revisions, 1.36 [1.13–1.64], p = 0.001). Higher Charlson comorbidity score (HR for a score of 5+ versus 0, 2.56 [2.12–3.14], p < 0.001), obesity (HR, 1.14 [1.00–1.30], p = 0.044), deep vein thrombosis (HR, 1.34 [1.12–1.60], p = 0.001), and additional revisions (HR for 2+ additional revisions, 2.19 [1.91–2.49], p < 0.001) were factors associated with AKA, which in turn was an independent risk factor for mortality. The risk of death increased with amputation after adjusting for age, comorbidities, and other factors (HR, 1.28 [1.20–1.37], p < 0.001), but patients who received arthrodesis did not show a change in mortality compared with the patients who did not receive arthrodesis or amputation (HR, 1.00 [0.91–1.10], p = 0.971).

Conclusions

The findings of this study suggest that clinicians may be more aggressively attempting to preserve the knee even in the face of chronic prosthetic joint infection but also show that a greater number of revisions is associated with a greater risk of subsequent AKA or arthrodesis. The results also suggest that recommending centers with a high volume of joint arthroplasties may be a way to reduce the risk of the salvage procedures.

Level of Evidence

Level III, therapeutic study.

     

Implant Survival,Knee Function,and Pain Relief After TKA: Are There Differences Between Men and Women?

Background  

As efforts continue to improve the results of TKA, the potential influence of sex and gender on long-term survival of implants, knee function, pain relief, and patient satisfaction remains relevant, particularly given the increased incidence of osteoarthritis of the knee in women and reports that women derive equal benefit from TKA.     

Is There an Association Between Hemoglobin A1C and Deep Postoperative Infection After TKA?

Clinical Orthopaedics and Related Research® - Despite substantial research into the use of glycemic markers to stratify infection risk in patients with diabetes mellitus, there is little...     

Definitional Differences of ‘Outpatient’ Versus ‘Inpatient’ THA and TKA Can Affect Study Outcomes

Background

There has been great interest in performing outpatient THA and TKA. Studies have compared such procedures done as outpatients versus inpatients. However, stated “outpatient” status as defined by large national databases such as the National Surgical Quality Improvement Program (NSQIP) may not be a consistent entity, and the actual lengths of stay of those patients categorized as outpatients in NSQIP have not been specifically ascertained and may in fact include some patients who are “observed” for one or more nights. Current regulations in the United States allow these “observed” patients to stay more than one night at the hospital under observation status despite being coded as outpatients. Determining the degree to which this is the case, and what, exactly, “outpatient” means in the NSQIP, may influence the way clinicians read studies from that source and the way hospital systems and policymakers use those data.

Questions/Purposes

The purposes of this study were (1) to utilize the NSQIP database to characterize the differences in definition of “inpatient” and “outpatient” (stated status versus actual length of stay [LOS], measured in days) for THA and TKA; and (2) to study the effect of defining populations using different definitions.

Methods

Patients who underwent THA and TKA in the 2005 to 2014 NSQIP database were identified. Outpatient procedures were defined as either hospital LOS = 0 days in NSQIP or being termed “outpatient” by the hospital. The actual hospital LOS of “outpatients” was characterized. “Outpatients” were considered to have stayed overnight if they had a LOS of 1 day or longer. The effects of the different definitions on 30-day outcomes were evaluated using multivariate analysis while controlling for potential confounding factors.

Results

Of 72,651 patients undergoing THA, 529 were identified as “outpatients” but only 63 of these (12%) had a LOS = 0. Of 117,454 patients undergoing TKA, 890 were identified as “outpatients” but only 95 of these (11%) had a LOS = 0. After controlling for potential confounding factors such as gender, body mass index, functional status before surgery, comorbidities, and smoking status, we found “inpatient” THA to be associated with increased risk of any adverse event (relative risk, 2.643, p = 0.002), serious adverse event (relative risk, 2.455, p = 0.011), and readmission (relative risk, 2.775, p = 0.010) compared with “outpatient” THA. However, for the same procedure and controlling for the same factors, patients who had LOS > 0 were not associated with any increased risk compared with patients who had LOS = 0. A similar trend was also found in the TKA cohort.

Conclusions

Future THA, TKA, or other investigations on this topic should consistently quantify the term “outpatient” because different definitions, stated status or actual LOS, may lead to different assignments of risk factors for postoperative complications. Accurate data regarding risk factors for complications after total joint arthroplasty are crucial for efforts to reduce length of hospital stay and minimize complications.

Level of Evidence

Level III, therapeutic study.