The Short Form KOOS, JR Is Valid for Revision Knee Arthroplasty.

BACKGROUND: The Knee Injury Osteoarthritis Outcome Survey, Joint Replacement (KOOS, JR) is a reliable, responsive, and validated patient-reported outcome measure (PROM) of knee health in patients with knee osteoarthritis undergoing unilateral primary total knee arthroplasty (TKA). The validity of the KOOS, JR for revision TKA remains unknown. METHODS: We identified 314 patients who underwent revision TKA and had completed preoperative and 2-year postoperative PROMs. Validation included assessment of local dependence, unidimensionality, internal consistency, external construct validity, responsiveness, and floor effects preoperatively and ceiling effects at 2 years postoperatively. RESULTS: Among patients undergoing revision TKA, the KOOS, JR demonstrated an absence of residual item correlation, adequate unidimensionality, high internal consistency (Person Separation Index: 0.897), and high external construct validity with existing validated PROMs, including KOOS Pain (Spearman's correlation coefficient 0.89) and KOOS activities of daily living (0.90) domains. The KOOS, JR was more responsive (standardized response means: 1.14) to revision TKA than other common knee PROMs. Three percent of revision TKA patients were at the floor (lowest score) preoperatively and 9% reached the ceiling (highest possible score) postoperatively. CONCLUSIONS: KOOS, JR performs well in revision TKA patients with regard to internal consistency, external validity, responsiveness, and floor and ceiling effects. Our results support extending its use to revision TKA in both clinical and research settings.

Age-Related Decline in Patient-Reported Outcomes 2 and 5 Years Following Total Hip Arthroplasty.

BACKGROUND: Patient-reported outcome measures (PROMs) help assess therapeutic effectiveness. This study assessed the effect of advanced age on the Hip Disability and Osteoarthritis Outcome Score (HOOS) and Lower Extremity Activity Scale (LEAS) after total hip arthroplasty (THA). METHODS: A prospective cohort of patients underwent primary THA at our institution between May 2007 and December 2011. Exposure was age at the time of surgery and outcomes were HOOS and LEAS scores 2 and 5 years postsurgery. We used a multivariable longitudinal generalized estimating equation to elucidate the effect of age on PROM scores. RESULTS: Our analysis of 3700 THA patients (mean age, 66 years; 56.4% female) demonstrated a decline in scores by age for the LEAS, HOOS Activities of Daily Living, and HOOS Sport and Recreation domains. There was also association between age and HOOS Symptoms and HOOS Quality of Life domains, but not between age and the HOOS Pain domain. Critical ages at which the relationship between age and outcome changed was 63 years for the HOOS Pain, Symptom, Activities of Daily Living, and Quality of Life domains, and 72 years for the HOOS Sport and Recreation domain and the LEAS. CONCLUSION: Patients undergoing THA at older ages reported lower activity and sports and recreation scores than younger patients, but similar pain, symptoms, and quality of life scores. This knowledge can help physicians guide patients' expectations before THA. Our findings also indicate that PROM scores should be age adjusted when used for quality or value comparisons between hospitals or physicians.

Patient-Reported Outcome Measures of Total Knee Arthroplasties for Post-Traumatic Arthritis versus Osteoarthritis: A Short-Term (5- to 10-year) Retrospective Matched Cohort Study.

BACKGROUND: The objective of the study was to compare the patient-reported outcome measures (PROM) of patients with post-traumatic arthritis (PTA) versus patients with osteoarthritis (OA) undergoing total knee arthroplasty (TKA) and compare the rates of revision among these two groups. METHODS: Using a prospectively held institutional registry, we retrospectively reviewed patients ≥60 years of age who underwent unilateral TKA between May 2007 and February 2012. Patients with previous or concomitant diagnosis of inflammatory arthropathy or an initial open fracture were excluded. PTA patients were matched 1:5 with OA patients undergoing TKA. Validated PROMs were recorded at baseline before index TKA and the last follow-up. Reason and time to revision surgery was reported, and survivorship was compared using Kaplan-Meier curves. RESULTS: Seventy-five PTA patients were matched to 375 OA patients. There was no difference between these groups with respect to age (67.7 ± 5.6 vs 67.8 ± 5.5 years; P = .876), body mass index (28.6 ± 5.4 vs 28.7 ± 5.3 kg/m2; P = .948), sex (65.3% vs 65.3% females; P = .999), Charlson Comorbidity Index (21.3% vs 21.3% Index 1-2, P = .999), and time to follow-up (93.0 ± 13.4 vs 88.2 ± 13.7 months; P = .999). No statistically significant difference was found in PROMs at baseline and the last follow-up (P > .05), the rate or time to revision surgery between the two groups (P-value = .635; log-rank test). CONCLUSION: Unlike previous studies, TKA for PTA does not pose lower PROMs or higher revision rates when compared to TKA for OA. These results could help provide surgeons with a frame of reference in terms of expectations for patients with PTA undergoing TKA.

What Are the Minimal and Substantial Improvements in the HOOS and KOOS and JR Versions After Total Joint Replacement?

BACKGROUND: Patient-reported outcome measures (PROMs) are a gold standard for measuring therapeutic outcomes in research. Extending their use to inform clinical care decisions, determine the appropriateness of therapeutic choices, and assess healthcare quality is attractive but will require our professional community to establish valid estimates of minimal and substantial clinical improvements. QUESTIONS/PURPOSES: The purposes of this study were (1) to assess the validity of estimates for the minimal clinically important difference (MCID) calculated using distribution- and anchor-based methods by determining whether they exceed the minimal detectable change (MDC) for the Hip Disability and Osteoarthritis Outcome Score (HOOS) and the Knee Injury and Osteoarthritis Outcome Score (KOOS) domains, the HOOS, joint replacement (JR) and the KOOS, JR among patients who underwent THA or TKA; (2) to determine substantial clinical benefit thresholds for the HOOS and KOOS domains, the HOOS, JR, and the KOOS, JR among patients who underwent THA or TKA; and (3) to assess the proportions of patients who underwent THA or TKA who achieved an MCID for the HOOS and KOOS domains, HOOS, JR, and KOOS, JR based on distribution-based and anchor-based methods as well as the percentages of patients who achieved substantial clinical benefit using the anchor-based method. METHODS: Medicare patients enrolled in our institutional joint replacement registry who subsequently underwent THA (n = 2323) or TKA (n = 2630) between 2007 and 2012 completed HOOS or KOOS preoperatively and 2 years postoperatively. Short-form joint replacement (JR) versions of each PROM were derived from the full PROMs. Of all eligible patients, 78% (3161 of 4080) of THAs and 74% of TKAs (3815 of 5156) consented to join the registry and completed a baseline survey, 88% (2796 of 3161) of THAs and 85% (3230 of 3815) of TKAs were eligible for followup survey administration, and 83% of THAs (2323 of 2796) and 81% (2630 of 3230) of TKAs returned 2-year surveys. For each HOOS domain, KOOS domain, HOOS, JR, and KOOS, JR, we calculated the calibration variation of the instrument (MDC) with confidence intervals (CIs) reflecting 80% (MDC80), 90% (MDC90), and 95% (MDC95) certainty; we calculated the smallest difference joint health patients might detect (MCID) using distribution- and anchor-based approaches and the difference that can be considered a large improvement in joint health (substantial clinical benefit) using an anchor-based approach. RESULTS: Patients undergoing THA were 57% female with a mean (± SD) age of 73 ± 6 years, whereas patients undergoing TKA were 63% female with a mean age of 74 ± 6 years. Depending on the CI chosen for the MDC, values ranged from 7 to 16 for the HOOS and KOOS domains and the JRs. The MCIDs ranged from 6 to 9 for the distribution-based approach and 7 to 36 for the anchor-based approach. All HOOS and KOOS domains and all JR scores are scores from 0 (worst joint health) to 100 (best joint health). The MCIDs calculated using the distribution-based approach were not valid, because they were lower than the MDC for all HOOS/KOOS domains and both JRs at every confidence level. The anchor-based receiver operating characteristic approach, on the other hand, resulted in MCIDs exceeding MDC80 for seven of eight HOOS/KOOS domains and MDC95 for both JR scores. For all domains and JR versions, substantial clinical benefits ranged from 15 to 36, exceeding MDC95 in all domains and JR scores. Across HOOS and KOOS domains as well as the JR, the proportion of patients undergoing THA who achieved an MCID ranged from 77% to 95% with the distribution-based method and from 67% to 96% using the anchor-based method. The proportion achieving substantial clinical benefit ranged from 67% to 85%. CONCLUSIONS: The MDC and MCID differ greatly based on assumptions and methods used. The MCID anchor-based approach had superior construct and face validity compared with the MCID distribution-based approach, which never exceeded even small MDCs. Achieving consensus about standard definitions of meaningful improvement will be necessary to maximize utility of these PROMs to inform clinical care or performance measurement. LEVEL OF EVIDENCE: Level III, diagnostic study.

Satisfaction Rates and Quality of Life Changes Following Total Knee Arthroplasty in Age-Differentiated Cohorts.

BACKGROUND: Comparisons of satisfaction rates following total knee arthroplasty (TKA) among large, age-differentiated, rigorously matched cohorts are lacking. Therefore, we compared satisfaction rates following TKA in large, age-differentiated, propensity score-matched cohorts. METHODS: We identified primary TKAs performed for non-inflammatory arthritis in patients of ages 18-55 or 65-75, yielding 529 younger and 2001 older patients. Patient-reported outcomes were recorded pre-operatively and 2 years post-operatively. 1:1 propensity score matching between groups yielded 529 patient pairs. Matching was based on gender, body mass index, American Society of Anesthesiologists grade, Charlson Comorbidity Index, and Short Form 12 Mental Health Component score. Outcomes were compared between matched groups using t-test and Wilcoxon rank-sum test. RESULTS: Satisfaction with knee surgery was 86% among younger patients and 91% among older patients. Distribution of satisfaction responses was shifted toward greater satisfaction in older patients (P < .001). Overall quality of life (QOL) improvement was 91% among younger patients and 96% among older patients. Pre-operative and post-operative knee-related QOL was better among older patients (P < .0001). Post-operative global health-related QOL was equivalent between groups based on Short Form 12 Physical Component Score and Mental Health Component score (P = .6646 and P = .5705, respectively) and QOL improvement questionnaires (P = .181). Younger patients reported greater knee-related dysfunction and higher activity levels pre-operatively and post-operatively (P ≤ .0002). CONCLUSION: Satisfaction with knee surgery was over 85% regardless of age. Younger patients perceived more knee-related dysfunction and dissatisfaction after surgery despite higher levels of self-reported activity pre-operatively and post-operatively.

Venous Hemodynamics After Total Hip Arthroplasty: A Comparison Between Portable vs Stationary Pneumatic Compression Devices and the Effect of Body Position.

BACKGROUND: Improvements in device design have allowed for portable pneumatic compression devices (PPCDs). However, portability results in smaller pumps that move less blood. Additionally, although patients often stand when wearing PPCDs, few studies have evaluated the hemodynamic effects of PCDs while standing. METHODS: A crossover study was performed to compare a PPCD (ActiveCare+S.F.T.; Medical Compression Systems, Or Akiva, Israel) to a stationary pneumatic compression device (SPCD) (VenaFlow; DJO Global, Carlsbad, CA) on hemodynamics in supine and standing positions among 2 cohorts composed of 10 controls and 10 total hip arthroplasty patients. Differences in baseline peak venous velocity (PVV), PVV with each PCD, and delta PVV with each PCD were assessed. A multivariate analysis was performed to examine differences between cohorts, devices, and position. RESULTS: In both positions, the SPCD demonstrated a larger change in PVV when compared to the PPCD (P < .001). The total hip arthroplasty group had a greater delta PVV while standing when considering both PCDs together (P < .001). When considering both cohorts, delta PVV was greater while standing, only when the SPCD was used (P < .001). There was no difference between standing and supine positions when the PPCD was used. CONCLUSION: The SPCD demonstrated a greater capacity to increase PPV in the supine and standing positions. The SPCD generated greater values of PVV and delta PVV in the standing position. Although these results demonstrate a difference between devices, it is important to establish the PVV necessary to prevent VTE before one is considered more effective.

In-Hospital Morbidity and Postoperative Revisions After Direct Anterior vs Posterior Total Hip Arthroplasty.

BACKGROUND: The direct anterior approach (DAA) offers the potential for less soft tissue insult, improved early recovery, and reduced dislocation rates. However, complications are associated with the DAA, particularly during the learning curve. We compare the DAA learning curve experience with the posterior approach regarding in-hospital complications and revision rate. METHODS: We evaluated systemic and local in-hospital complications associated with primary unilateral cementless THAs from January 1, 2010 to December 31, 2012 in 4249 patients through a posterior approach and 289 patients through a DAA. All procedures were performed consecutively by high-volume surgeons who use a single approach in a nonselective manner. The DAA was performed by surgeon transitioning from the posterior approach, thus incorporating the learning curve. Demographics were comparable. Revision procedures were captured through a minimum 4-year follow-up. Analyses compared complication and revision rates. RESULTS: The DAA group demonstrated shorter length of stay, procedure time, lower blood transfusion rate, and increased discharge to home rate. Local and major systemic in-hospital complications were rare and comparable between groups. The minor systemic complication rate was significantly greater for the posterior group (10.9% posterior vs 6.2% DAA, P < .05). Revision rate was significantly greater for the posterior group (2.7% posterior vs 0.7% DAA, P < .032). The incidence of revision for dislocation was 1.5% for the posterior approach vs 0.4% for the DAA. CONCLUSION: There was an increased rate of in-hospital minor systemic complications and overall revision, predominantly due to instability, after THA by the posterior approach, in comparison with the DAA.

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.

Polished, Collarless, Tapered, Cemented Stems for Primary Hip Arthroplasty May Exhibit High Rate of Periprosthetic Fracture at Short-Term Follow-Up.

BACKGROUND: Cemented stems are designed to follow 1 of 2 principles of fixation: composite beams or slide taper. Stems in the latter category have a collarless, polished, tapered (CPT) design and subside into the cement mantle, creating hoop stresses. We compared the rate of periprosthetic fracture (PPF) of stem designed with these 2 principles of fixation. In addition, we examined radiographic factors that may predispose to the development of PPF. METHODS: We retrospectively reviewed all patients who underwent primary THA by a single surgeon using highly polished cemented stems. PPF rates were compared between CPT stems (follow-up, 21 months; standard deviation [SD], 22) and composite beam stems (follow-up, 21.7 months; SD, 26). Demographic data were compared between patients with and without a PPF. Three preoperative radiographic parameters (canal bone ratio [CBR], canal-calcar ratio, and canal flare index), stem alignment, and cement mantle were compared in match-paired patients with and without a PPF (1:34). RESULTS: Seven of 1460 THA patients developed a PPF (0.479%); 4 hips of 185 with a CPT stem (2.2%); and 3 of 1275 hips with a composite beam stem (0.23%; P = .0064). Three of the 4 PPFs in the CPT group and none in the composite beam group were classified as Vancouver B2. The CBR in patients with a PPF was 0.50 (SD, 0.07) and 0.43 (SD, 0.07) in the match cohort of hips without PPF (P = .013). CONCLUSION: CPT stems may be associated with a higher risk of PPF that often require reoperation. An increased CBR may be a risk factor for postoperative PPF.

Failure After Modern Total Knee Arthroplasty: A Prospective Study of 18,065 Knees.

BACKGROUND: We sought is to determine the mechanism of failure among primary total knee arthroplasties (TKAs) performed at a single high-volume institution by asking the following research questions: (1) What are the most common failure modes for modern TKA designs? and (2) What are the preoperative risk factors for failure following primary TKA? METHODS: From May 2007 to December 2012, 18,065 primary TKAs performed on 16,083 patients at a single institution were recorded in a prospective total joint arthroplasty registry with a minimum of 5-year follow-up. We retrospectively reviewed patient charts to determine a cause of failure for primary TKAs. A cox proportional hazard model was used to determine the risk of revision surgery following primary TKA. RESULTS: The most common reasons for failure within 2 years after TKA were infection and stiffness. The multivariable regression identified the following preoperative risk factors for TKA failure: history of drug abuse (hazard ratio [HR] 4.68; P = 0.03), deformity/mechanical preoperative diagnosis (HR 3.52; P < .01), having a constrained condylar knee implant over posterior-stabilized implant (HR 1.99; P < .01), post-traumatic/trauma preoperative diagnosis (HR 1.78; P = .03), and younger age (HR 0.61; P < .01) CONCLUSION: These findings add to the growing data that primary TKAs are no longer failing from polyethylene wear-related issues. This study identified preoperative risk factors for failure of primary TKAs, which may be useful information for developing strategies to improve outcomes following TKA.

Implant Survival and Patient-Reported Outcomes After Total Hip Arthroplasty in Young Patients.

BACKGROUND: Younger patients are undergoing total hip arthroplasty (THA) for various conditions that affect the hip joint. This study evaluates the implant survival and long-term patient-reported outcomes of THA in patients aged 35 years or younger. METHODS: Data were collected through a retrospective chart review, and follow-up surveys were conducted to determine implant survival and patient-reported outcomes. Kaplan-Meier survival analysis was performed to evaluate implant survival, and the hip disability and osteoarthritis outcome score (HOOS) was used to describe patient-reported outcomes. Descriptive statistics were used to summarize baseline and follow-up data, and univariate and multivariate analyses were used to compare implant survival and patient-reported outcomes. RESULTS: This study included 400 patients (548 THAs). The average age at the time of surgery was 27 (range: 8-35) years, and the mean time to follow-up was 14 (range: 2-29.7) years. The 10- and 20-year implant survival was 87% and 61%, respectively. Implant survival differed based on primary diagnosis (P = .05), and it was significantly better in patients aged 25 years or older at the time of surgery, male patients, and patients with ceramic-on-ceramic or ceramic-on-plastic implants (P < .05). Mean HOOS scores at follow-up were 86 for pain, 84 for symptoms, 86 for ADLs, and 77 for sports. All HOOS scores were significantly worse after revision THA (P < .01). CONCLUSION: Young patients have good implant survival and favorable long-term outcomes after THA. There are several predictors of implant survival and patient-reported outcomes after THA in young patients.

Polyethylene Damage Increases With Varus Implant Alignment in Posterior-stabilized and Constrained Condylar Knee Arthroplasty.

BACKGROUND: Implant malalignment in primary TKA has been reported to increase stresses placed on the bearing surfaces of implant components. We used a longitudinally maintained registry coupled with an implant retrieval program to consider whether preoperative, postoperative, or prerevision malalignment was associated with increased risk of revision surgery after TKA. QUESTIONS/PURPOSES: (1) What is the relative polyethylene damage on medial and lateral compartments of the tibial plateaus from revised TKAs? (2) Does coronal TKA alignment affect implant performance, such that TKAs aligned in varus are predisposed to experience increased polyethylene damage? (3) Does TKA alignment differ between postoperative and prerevision radiographs, and if so, what does this difference suggest about the mechanical contact load placed on a knee with a TKA? METHODS: Between 2007 and 2012, we performed 18,065 primary TKAs at our institution. By March 2016, 178 of those TKAs (1%) were revised at our center at least 2 years after primary surgery at our institution. Eighteen of those TKAs were excluded from this analysis because the tibial insert was not explanted during revision surgery, and four more were excluded because the inserts were lost or returned to the patient before the study was initiated, leaving 156 retrieved polyethylene tibial inserts (in 153 patients) revised at greater than 2 years after the primary TKA for this retrospective study. Patients who underwent revision surgery elsewhere were not considered here, since this study depended on having retrieved components. Polyethylene damage modes of burnishing, pitting, scratching, delamination, surface deformation, abrasion, and third-body debris were subjectively graded on a scale of 0 to 3 to reflect the extent and severity of each damage mode. On preoperative, postoperative, and prerevision radiographs, overall alignment, femoral alignment, and tibial alignment in the coronal plane were measured according to the protocol recommended by the Knee Society. RESULTS: Knees with more overall varus alignment after TKA had increased total damage on the retrieved tibial inserts (Spearman's rank correlation coefficients of -0.3 [95% CI, -0.4 to -0.1; p = 0.001]). We also found revised TKAs tended to drift back into greater varus before revision surgery, with a mean (SD) of 3.6° ± 4.0° valgus for postoperative alignment compared with 1.7° ± 6.4° prerevision (p = 0.04). CONCLUSIONS: Despite surgical efforts to achieve neutral mechanical alignment, remaining varus alignment places an increased contact load on the polyethylene articular surfaces. The drift toward further varus alignment postoperatively is consistent with the knee adduction moment remaining high after surgery. CLINICAL RELEVANCE: While we found a predisposition toward recurrence of the preoperative varus deformity, we did not find increased medial as opposed to lateral polyethylene damage, which may be explained by the curve-on-curve toroidal design of the articulating surfaces of the TKA implants in this study.

A Crosswalk Between UCLA and Lower Extremity Activity Scales.

BACKGROUND: The University of California, Los Angeles (UCLA) activity scale and the Lower Extremity Activity Scale (LEAS) are the two most-widely used and rigorously developed scales for assessing activity level in patients having joint replacement. However, the two scales are not convertible, and the level of correlation between the two is not clear. Creating a crosswalk between these scales; that is, a concordance table to convert scores from one scale to the other and vice versa, will help compare results from existing studies using either scale, and pool those results for meta-analyses. It also will facilitate pooling data from multiple registries and data sources. QUESTIONS/PURPOSE: To create a crosswalk between the UCLA and the LEAS activity scales for patients having THA or TKA. METHODS: Preoperative and 2-year postoperative UCLA and LEAS scores for a cohort of patients undergoing primary TKA or THA at the Hospital for Special Surgery between May 2007 and December 2011 were matched from two registries. The scales were self-administered by patients. Three hundred sixty-four patients having TKAs (67% women; mean age, 67 years) and 403 having THA (66% women; mean age, 66 years) had both scores available. The equipercentile equating method was used to create the crosswalk. The standard response mean was used to assess responsiveness of the converted versus actual UCLA and LEAS scores from baseline to 2 years. Crosswalk validation also included comparing the area under the receiver operating characteristic curve of the actual and converted scores to evaluate their ability to discriminate different levels of function measured using the Hip dysfunction and Osteoarthritis Outcome Score activities of daily living subscale for patients having THA and the Knee injury and Osteoarthritis Outcome Score activities of daily living subscale for patients having TKA. Difference between scores was assessed using the inequality test. RESULTS: For patients having TKA, converted mean scores (UCLA to LEAS, 9.5 ± 3.0; LEAS to UCLA, 4.7 ± 2.1) were not different from the actual scores (UCLA, 4.8 ± 2.1; LEAS, 9.4 ± 2.9). Standard response means for the converted scores (UCLA to LEAS, 0.47; LEAS to UCLA, 0.52) were not different from those of the actual scores (UCLA, 0.48; LEAS, 0.56). The areas under the receiver operating characteristic curve also were not different for actual and converted scores for THA and TKA. CONCLUSION: We have developed and validated a crosswalk to easily convert UCLA to LEAS scores (and vice versa) for THA and TKA. Reproducing the crosswalk for other lower extremity conditions or surgical procedures may extend its utility to studies assessing activity in patients having these conditions or procedures.

Incidence, indications, outcomes, and survivorship of stems in primary total knee arthroplasty.

PURPOSE: The indications, incidence, outcomes, and survivorship of stems in primary total knee arthroplasty (TKA) are lacking in the contemporary literature. Our hypothesis is stems in primary TKA would result in worse outcomes and survivorship. METHODS: All primary TKAs between 2007 and 2011 with 2-year follow-up were identified. Revision TKA or UKA conversion was excluded. Demographic information (age, sex, race, BMI, primary diagnosis, and Charlson-Deyo comorbidity index), outcome measures including KOOS and WOMAC, and any revisions were identified from the registry. A 2:1 matched cohort of non-stemmed/stemmed primary TKA patients was created to compare revision rates and outcomes at baseline and 2 years post-TKA. Subgroup analyses of long versus short stems, 1 versus 2 stems, and cemented versus hybrid stem fixation were completed. Two-sample t tests and Chi-square tests were used to compare conventional and stemmed TKA groups. RESULTS: The registry review included 13,507 conventional TKA and 318 stemmed TKA resulting in an incidence of 2.3 % in primary TKA. The mean follow-up was approximately 49 months in both groups. No difference was found in revision rates between stemmed TKA (2.5 %) and conventional TKA (2.2 %). Patients with post-traumatic arthritis had an odds ratio of 10.5 (95 % CI 1.2-15.3) of receiving stems. Stem length did not affect revision rates. Patients with two stems had worse KOOS and WOMAC scores at baseline which equalized to single-stem patients at 2 years. CONCLUSIONS: The use of stems may provide a survival benefit in complex primary TKA over the short term and no adverse effect on patient outcomes or satisfaction. LEVEL OF EVIDENCE: III.

Clinical Outcomes Following the Use of Constrained Condylar Knees in Primary Total Knee Arthroplasty.

BACKGROUND: Certain clinical or adverse intraoperative situations require the use of increased constraint in primary total knee arthroplasty (TKA). These include significant angular deformities causing incompetent collateral ligaments, or inadvertent intraoperative injury to collateral structures as well as the inability to achieve a balanced flexion and extension gap. Clinical success has been described with the use of constrained condylar knee arthroplasty in the primary setting in these situations. Traditionally, increasing constraint has been in conjunction with intramedullary stems, referred to as stemmed constrained condylar knees (SCCK); however, some devices provide an intermediary option by increasing constraint without the use of stems, herein referred to as nonstemmed constrained condylar knees (NSCCK). The aim of this study was to compare the clinical outcomes of both these devices in primary TKA in terms of revision rates and change in outcome measures over the follow-up period. METHODS: Between 2007 and 2012, 85 SCCKs and 354 NSCCKs were identified in our institutional registry database performed in the primary TKA setting with minimum 2-year clinical outcome measure follow-up. Baseline demographic information, as well as Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Lower Extremity Activity Scale (LEAS) were collected preoperatively at 2-year follow-up. Revision data were also collected. RESULTS: Both groups showed substantial improvement in WOMAC scores (pain, stiffness, and function), and LEAS at 2 years postoperatively compared with baseline, although the changes in scores were not statistically significant. One of 85 SCCKs (1.17%) was revised for infection, whereas 9 of 354 NSCCKs (2.54%) were revised (6 for mechanical complications, eg, loosening, 2 for periprosthetic fracture, and 1 for infection). CONCLUSION: Both cohorts demonstrated improvement in clinical outcome measures at 2-year follow-up. None of the SCCKs performed in the primary setting were revised for a mechanical complication. Although both groups had overall low revision rates, there was trend toward a higher revision rate with NSCCKs. Many of these were revised for component loosening. In summary, when necessary, constrained options in the primary TKA setting provide excellent clinical outcome at short-term follow-up. However, constrained constructs with stemmed fixation may provide more rigid fixation and be less susceptible to mechanical failure.

Patient and Perioperative Variables Affecting 30-Day Readmission for Surgical Complications After Hip and Knee Arthroplasties: A Matched Cohort Study.

BACKGROUND: Changes in reimbursement for total hip and knee arthroplasties (THA and TKA) have placed increased financial burden of early readmission on hospitals and surgeons. Our purpose was to characterize factors of 30-day readmission for surgical complications after THA and TKA at a single, high-volume orthopedic specialty hospital. METHODS: Patients with a diagnosis of osteoarthritis and who were readmitted within 30 days of their unilateral primary THA or TKA procedure between 2010 and 2014. Readmitted patients were matched to nonreadmitted patients 1:2. Patient and perioperative variables were collected for both cohorts. A conditional logistic regression was performed to assess both the patient and perioperative factors and their predictive value toward 30-day readmission. RESULTS: Twenty-one thousand eight hundred sixty-four arthroplasties (THA = 11,105; TKA = 10,759) were performed between 2010 and 2014 at our institution, in which 60 patients (THA = 37, TKA = 23) were readmitted during this 5-year period. The most common reasons for readmission were fracture (N = 14), infection (N = 14), and dislocation (N = 9). Thirty-day readmission for THA was associated with increased procedure time (P = .05), length of stay (LOS) shorter than 2 days (P = .04), discharge to a skilled nursing facility (P = .05), and anticoagulation use other than aspirin (P = .02). Thirty-day readmission for TKA was associated with increased tourniquet time (P = .02), LOS <3 days (P < .01), and preoperative depression (P = .02). In the combined THA/TKA model, a diagnosis of depression increased 30-day readmission (odds ratio 3.5 [1.4-8.5]; P < .01). CONCLUSION: Risk factors for 30-day readmission for surgical complications included short LOS, discharge destination, increased procedure/tourniquet time, potent anticoagulation use, and preoperative diagnosis of depression. A focus on risk factor modification and improved risk stratification models are necessary to optimize patient care using readmission rates as a quality benchmark.

Body Mass Index Class Is Independently Associated With Health-Related Quality of Life After Primary Total Hip Arthroplasty: An Institutional Registry-Based Study.

BACKGROUND: The purpose of this study was to compare the health-related quality of life (HRQoL) of patients across World Health Organization (WHO) body mass index (BMI) classes before and after total hip arthroplasty (THA). METHODS: Patients with end-stage hip osteoarthritis who received elective primary unilateral THA were identified through an institutional registry and categorized based on the World Health Organization BMI classification. Age, sex, laterality, year of surgery, and Charlson-Deyo comorbidity index were recorded. The primary outcome was the EQ-5D-3L index and visual analog scale (EQ-VAS) scores at 2 years postoperatively. Inferential statistics and regression analyses were performed to determine associations between BMI classes and HRQoL. RESULTS: EQ-5D-3L scores at baseline and at 2 years were statistically different across BMI classes, with higher EQ-VAS and index scores in patients with lower BMI. There was no difference observed for the 2-year change in EQ-VAS scores, but there was a statistically greater increase in index scores for more obese patients. In the regression analyses, there were statistically significant negative effect estimates for EQ-VAS and index scores associated with increasing BMI class. CONCLUSION: BMI class is independently associated with lower HRQoL scores 2 years after primary THA. While absolute scores in obese patients were lower than in nonobese patients, obese patients enjoyed more positive changes in EQ-5D index scores after THA. These results may provide the most detailed information on how BMI influences HRQoL before and after THA, and they are relevant to future economic decision analyses on the topic.

Survivorship of Extensor Mechanism Allograft Reconstruction After Total Knee Arthroplasty.

BACKGROUND: Extensor mechanism disruption remains a devastating complication after total knee arthroplasty. The purpose of this study is to describe the outcomes of extensor mechanism allograft (EMA) reconstruction in a large single-center case series. METHODS: Consecutive patients with a previous total knee arthroplasty undergoing extensor mechanism reconstruction using a fresh-frozen EMA tensioned in full extension were identified retrospectively from single-center institutional database (N = 25 patients, 26 knees; mean follow-up 68 months [range 22-113 months]). The primary outcome was initial allograft failure, defined as removal of the allograft or extensor lag >30 degrees at most recent follow-up. RESULTS: Sixty-nine percent (18/26) of knees had retained their initial allograft reconstruction at their latest follow-up despite reoperation rates of 58% (15/26). A younger age was significantly associated with failure of the initial allograft reconstruction. Knee Society Scores increased from 101 (38 standard deviation [SD]) to 116 (40 SD) at most recent follow-up for the group as a whole (P = .4). Patients undergoing a reoperation for any cause had lower Knee Society Scores (101 [SD 38] vs 138 [SD 32], respectively; P = .04) at most recent follow-up. CONCLUSION: EMA reconstruction shows adequate overall intermediate-term survival; however, reoperation rates were high and associated with worse functional outcomes.

What Are Normal Metal Ion Levels After Total Hip Arthroplasty? A Serologic Analysis of Four Bearing Surfaces.

BACKGROUND: The recent experiences with adverse local tissue reactions have highlighted the need to establish what are normal serum levels of cobalt (Co), chromium (Cr), and titanium (Ti) after hip arthroplasty. METHODS: Serum Co, Cr, and Ti levels were measured in 80 nonconsecutive patients with well-functioning unilateral total hip arthroplasty and compared among 4 bearing surfaces: ceramic-on-ceramic (CoC); ceramic-on-polyethylene (CoP); metal-on-polyethylene (MoP), and dual mobility (DM). The preoperative and most recent University of California, Los Angeles (UCLA) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were compared among the different bearing surfaces. RESULTS: No significant difference was found among serum Co and Cr levels between the 4 bearing surface groups (P = .0609 and P = .1577). Secondary analysis comparing metal and ceramic femoral heads demonstrated that the metal group (MoP, modular dual mobility (Stryker Orthopedics, Mahwah, NJ) [metal]) had significant higher serum Co levels compared with the ceramic group (CoC, CoP, MDM [ceramic]) (1.05 mg/L ± 1.25 vs 0.59 mg/L ± 0.24; P = .0411). Spearman coefficient identified no correlation between metal ion levels and patient-reported outcome scores. CONCLUSION: No serum metal ion level differences were found among well-functioning total hip arthroplasty with modern bearing couples. Significantly higher serum Co levels were seen when comparing metal vs ceramic femoral heads in this study and warrants further investigation. Metal ion levels did not correlate with patient-reported outcome measures.

The Clinical Severity of Patients Diagnosed With an In-Hospital Pulmonary Embolism Following Modern, Elective Joint Arthroplasty Is Unrelated to the Location of Emboli in the Pulmonary Vasculature.

BACKGROUND: In the event of a postoperative pulmonary embolism (PE), it is generally believed that patients with centrally located emboli will have worse clinical symptoms than those with segmental or subsegmental ones. We studied if a relationship exists between the clinical severity at the time of PE diagnosis and the location of the emboli within the pulmonary vasculature. METHODS: All 269 patients who developed an in-hospital, computed tomography pulmonary angiography-proved, PE following elective total hip arthroplasty or total knee arthroplasty in our institution were studied. The clinical severity of the PE was calculated using the Pulmonary Embolism Severity Index (PESI) that classifies patients in 5 classes (class 5: most severe). All computed tomography pulmonary angiographies were re-reviewed to determine the location of the emboli within the pulmonary vasculature (central, segmental, or subsegmental-unilateral or bilateral). The association between PESI and the PE location was examined. RESULTS: The most proximal location of the emboli was central in 62, segmental in 139, and subsegmental in 68. There were 180 unilateral and 89 bilateral PE patients. There was no association between the PESI and the location of the emboli within the pulmonary vasculature (P = .32). Patients with bilateral or unilateral lung involvement had similar PESI (P = .78). CONCLUSION: The PESI, a recognized, validated predictor of mortality after PE was similar in patients with central, segmental, or subsegmental PE; and in patients with unilateral or bilateral lung involvement. The present study may aid clinicians while assessing and discussing the severity of PE symptoms with patients at the time of diagnosis.