The Role of Constraint in Revision Total Knee Replacement for Instability: Full Component Revision Vs Isolated Polyethylene Exchange in Selected Patients.

Background: Instability is a common indication for revision after total knee arthroplasty. Replacement of multiple components is the current standard, but isolated polyethylene liner exchange (IPE) may present a less-morbid alternative. This study aims to determine (1) whether IPE results in similar rerevision frequency to component revision in select patients with symptomatic instability and (2) the effect of increasing constraint on the outcome. Methods: We retrospectively reviewed 117 patients revised for symptomatic total knee arthroplasty instability from January 2016 to December 2017. The component revision (60 patients) or IPE (57 patients) cohorts were further stratified based on whether constraint was increased or not. The primary objective was to compare rerevision rates 2 years after component revision vs IPE. The secondary objectives consisted of evaluating reasons for rerevision, preoperative and postoperative patient-reported outcome measures, and range of motion. Results: The rerevision rate was 18%, with no statistical difference between component and IPE cohorts. Cases where level of constraint increased due to revision, a significantly lower rate of rerevision was detected (9 of 77) (12%) than in cases where constraint did not increase (12 of 39) (31%) (P=0.012). This association was also noted in the component revision cohort but not in the IPE cohort (P=0.011). Conclusions: Rerevision occurred at similar frequencies 2 years after IPE or component revision for total knee arthroplasty instability. For component revision, increased constraint was associated with significantly fewer rerevisions.

Transfusion Avoidance in Severely Anemic Total Hip and Total Knee Arthroplasty Patients: An Analysis of Risk.

Background: Allogenic blood transfusions increase the risk of multiple complications. We evaluated the influence of restricting transfusions in adults with osteoarthritis that underwent total hip or knee arthroplasty (THA/TKA) with severe postoperative anemia. Material and methods: Patients that underwent THA/TKA for osteoarthritis with postoperative hemoglobin (Hb) ≤ 8 g/dl were retrospectively identified. We evaluated characteristics and adverse postoperative outcomes of patients not transfused and compared them to those of patients who received postoperative transfusion. Adverse outcomes were 90-day readmission, reoperation, infection, and falls, as well as inpatient cardiovascular events and deaths. Results: One thousand eighty-seven patients meeting inclusion criteria underwent THA and TKA. The 399 patients (36.7%) who did not undergo transfuion were younger (67.4 vs 69.5 years, P = .008), healthier (American Society of Anesthesiologist ≤ 2: 64.2% vs 56%, P = .006), comprised a lower proportion of cardiovascular disease patients (13.8% vs 24.7%, P < .001), a lower proportion of patients with Medicare/Medicare Managed Care (57.2% vs 65.5%, P = .05), received tranexamic acid more frequently (66.4% vs 52.9%, P < .01), had a shorter procedure time (92.7 vs 103.1, P < .01), a lower postoperative drop in Hb (4.0 vs 4.2 g/dl, P = .022), a later drop in Hb (2.6 vs 2.2 days, P = .003), and a shorter length of stay (3.5 vs 4.8, P < .01). TKA patients underwent transfusion more frequently than THA patients (67.5% vs 59%, P = .004). There were no postoperative deaths. Adverse events were similar between the 2 groups. Conclusion: Findings suggest that younger and healthier patients that have lower Hb later during their hospital stay need not undergo transfusion solely based on Hb levels. Routine transfusion triggers can be avoided even in more anemic patients.

The Effect of Preoperative Tramadol Use on Postoperative Opioid Prescriptions After Primary Total Hip and Knee Arthroplasty: An Institutional Experience of 11,000 Patients.

BACKGROUND: Preoperative opioid use increases opioid consumption postoperatively, but the effect of tramadol is poorly understood. METHODS: We retrospectively reviewed 11,667 patients undergoing primary unilateral THA and TKA at a single institution. Preoperatively, there were 8,201 opioid-naïve patients (70.3%), 1,315 on tramadol (11.3%), 1,408 on narcotics (12.1%) and 743 on narcotics and tramadol (6.3%). We compared morphine milligram equivalents (MMEs) used during hospitalization, prescribed at discharge, and refilled during the first 90 days. We used multivariate analysis to assess whether preoperative tramadol use was associated with increased number of refills and total refilled MMEs. RESULTS: Total in-hospital MMEs and daily MMEs was lowest for the opioid naïve patients and significantly increased for the remaining three groups (total in-hospital use: 119, 152, 211, and 196 MMEs, respectively-P < .001) (daily in-hospital use: 66, 74, 100, and 86 MMEs, respectively-P < .001). Opioid refill rate was significantly higher for all patients who were not opioid naïve (32%, 42%, 41%, and 52%, respectively-P < .001). Total MMEs prescribed after discharge was lowest for opioid naïve patients (477, 528, 590 and 658, respectively-P < .001). Logistic and linear regression controlling for age, sex, history of anxiety/depression revealed that THA patients taking tramadol preoperatively were 2.5 times more likely to require post-discharge refills and refilled 80 additional MMEs than opioid naïve patients (P < .001). CONCLUSION: Tramadol is not recommended for pain beforeTKA or THA, and surgeons and patients should be aware that it is associated with a substantial increase in postoperative opioid use.

Predicting Post-Discharge Opioid Consumption After Total Hip and Knee Arthroplasty in the Opioid-Naïve Patient.

BACKGROUND: Pain catastrophizing, anxiety, and depression are associated with poor outcomes after total hip (THA) and total knee (TKA) arthroplasty. The goal of this study is to determine the relationship between post-operative pain scores and opioid consumption; and the association among pre-operative measures of anxiety, depression, and pain catastrophizing and post-operative opioid consumption in patients undergoing THA and TKA. METHODS: This is a single-institution prospective cohort study of 243 opioid-naïve patients undergoing elective, primary THA (n = 123) or TKA (n = 120) for osteoarthritis. Pre-operatively, patients completed the PROMIS-29 (Patient-Reported Outcomes Measures Information System; physical function/anxiety/depression/fatigue/sleep disturbance/social activities/pain interference/pain intensity) and Pain Catastrophizing Scale. Post-operatively, patients completed a weekly survey for 12 weeks determining morphine-milligram-equivalent (MME) opioid consumption, opioid cessation, and visual analog scale pain scores. Multivariable regression models determined the association between pre-operative scores and post-operative opioid consumption. RESULTS: Mean (±standard deviation) total opioid consumption and duration was 75.1 ± 112.0 MME and 1.7 ± 1.7 weeks in THA and 384.7 ± 473.3 MME and 4.3 ± 3.5 weeks in TKA. Visual analog scale pain scores (0-100) after opioid cessation were 28.0 ± 22.9 in THA and 30.7 ± 25.8 in TKA. Multivariable regression showed that each unit increase in PROMIS-29 fatigue T-score was associated with 8.4 hours longer opioid usage in THA (P = .008) and 15.1 hours longer in TKA (P = .036), as well as 12.7 MME additional opioids in TKA (P = .027). There were no significant associations with other PROMIS-29 domains or the Pain Catastrophizing Scale. CONCLUSION: Opioid use duration is different for THA and TKA and may correlate with pain scores. Only pre-operative fatigue was associated with post-operative opioid consumption. These findings should inform THA and TKA post-operative pain management pathways.

Development and Validation of Crosswalks Between the Western Ontario & McMaster Universities Osteoarthritis Index and Hip Disability and Osteoarthritis Outcome Score Joint Replacement/Knee Injury and Osteoarthritis Outcome Score Joint Replacement.

BACKGROUND: The wide variety of patient-reported outcome measures used to assess outcomes following total joint arthroplasty can present a substantial methodological obstacle when attempting to compare information across studies or between institutions. A simple solution is to create crosswalks that reliably convert scores between patient-reported outcome measures. Our goal is to create and validate crosswalks between the commonly used Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) and short-form versions of the Hip Disability and Osteoarthritis Outcome Score Joint Replacement (HOOS JR)/Knee Injury and Osteoarthritis Outcome Score (KOOS JR.). METHODS: Patients in our joint replacement registry were included if they underwent primary total hip arthroplasty (n = 4649) or total knee arthroplasty (n = 3750) for osteoarthritis between May 2007 and February 2012. We used their preoperative and 2-year postoperative HOOS scores (n = 6351) or KOOS scores (n = 4688) to generate the patients' WOMAC and HOOS JR/KOOS JR scores. The equipercentile equating method was applied to create 10 crosswalks: HOOS JR/KOOS JR to WOMAC Total (WOMAC-T), and WOMAC-T, WOMAC Pain (WOMAC-P), WOMAC Stiffness (WOMAC-S), and WOMAC Function (WOMAC-F) to HOOS JR/KOOS JR. Crosswalk validity was assessed by comparing actual and derived scores using Spearman's rank correlation coefficients in a bootstrapped cohort. RESULTS: All 10 crosswalks showed strong positive correlations ranging from 0.846 (WOMAC-S to KOOS JR) to 0.981 (HOOS JR to WOMAC-T). CONCLUSION: We created and validated 10 crosswalks between WOMAC and HOOS JR/KOOS JR. We recommend using the crosswalks between WOMAC-T and HOOS JR/KOOS JR when possible, as they demonstrated the highest correlation. WOMAC-F or WOMAC-P should be used in favor of WOMAC-S if only subscores are available. The HOOS JR/KOOS JR should only be converted to a WOMAC-T. LEVEL OF EVIDENCE: Level III.

Changes in opioid discharge prescriptions after primary total hip and total knee arthroplasty affect opioid refill rates and morphine milligram equivalents : an institutional experience of 20,000 patients.

AIMS: Due to the opioid epidemic in the USA, our service progressively decreased the number of opioid tablets prescribed at discharge after primary hip (THA) and knee (TKA) arthroplasty. The goal of this study was to analyze the effect on total morphine milligram equivalents (MMEs) prescribed and post-discharge opioid repeat prescriptions. METHODS: We retrospectively reviewed 19,428 patients undergoing a primary THA or TKA between 1 February 2016 and 31 December 2019. Two reductions in the number of opioid tablets prescribed at discharge were implemented over this time; as such, we analyzed three periods (P1, P2, and P3) with different routine discharge MME (750, 520, and 320 MMEs, respectively). We investigated 90-day refill rates, refill MMEs, and whether discharge MMEs were associated with represcribing in a multivariate model. RESULTS: A discharge prescription of < 400 MMEs was not a risk factor for opioid represcribing in the entire population (p = 0.772) or in opioid-naïve patients alone (p = 0.272). Procedure type was the most significant risk factor for narcotic represcribing, with unilateral TKA (hazard ratio (HR) = 5.62), bilateral TKA (HR = 6.32), and bilateral unicompartmental knee arthroplasty (UKA) (HR = 5.29) (all p < 0.001) being the highest risk for refills. For these three procedures, there was approximately a 5% to 6% increase in refills from P1 to P3 (p < 0.001); however, there was no significant increase in refill rates after any hip arthroplasty procedures. Total MMEs prescribed were significantly reduced from P1 to P3 (p < 0.001), leading to the equivalent of nearly 500,000 fewer oxycodone 5 mg tablets prescribed. CONCLUSION: Decreasing opioids prescribed at discharge led to a statistically significant reduction in total MMEs prescribed. While the represcribing rate did not increase for any hip arthroplasty procedure, the overall refill rates increased by about 5% for most knee arthroplasty procedures. As such, we are now probably prescribing an appropriate amount of opioids at discharge for knee arthroplasty procedure, but further reductions may be possible for hip arthroplasty procedures. Cite this article: Bone Joint J 2021;103-B(7 Supple B):103-110.

Reduction of Opioid Quantities at Discharge After TKA Did Not Increase the Risk of Manipulation Under Anesthesia: An Institutional Experience.

BACKGROUND: In response to the opioid epidemic, our arthroplasty service sequentially reduced the opioid quantities prescribed at primary total knee arthroplasty (TKA) discharge. However, its effect on postdischarge pain control and rehabilitation is unknown. We assessed if this decrease was associated with an increase in the risk of manipulation under anesthesia (MUA). METHODS: We retrospectively reviewed 8799 patients undergoing primary TKA from 2016 to 2019 at a single institution. There were two institution-wide reductions in the amount of opioids prescribed at discharge; therefore, we divided patients into 3 periods (P1, P2, and P3). The mean discharge morphine milligram equivalents (MMEs) went from 900 MMEs to ~525 MMEs to ~320 MMEs in P1, P2, and P3, respectively. We analyzed MUA rates and if lower discharge MMEs was a risk factor for MUA in a multivariate model. We also compared refill patterns (rates, number, refill MMEs, and total MMEs) between MUA and non-MUA patients. RESULTS: The rate of MUA did not increase with reduced discharged opioids (5.5% in P1, 5.8% in P2, and 4.6% in P3, P = .74). In a multivariate analysis, discharge MMEs of <450 was not a significant risk factor for MUA. However, a diagnosis of chronic pain (OR = 1.86, P < .001) and an elevated body mass index (OR = 1.02 per unit increase, P < .001) were significant risk factors. We did not find significant differences in any opioid prescription refill patterns in MUA and non-MUA patients. CONCLUSION: Serial reductions in discharge MMEs after primary TKA did not significantly affect the rate of MUA, a surrogate marker for pain control and the rehabilitative process.

High Rate of Re-Revision in Patients Less Than 55 Years of Age Undergoing Aseptic Revision Total Knee Arthroplasty.

BACKGROUND: There are limited data on the outcomes of revision total knee arthroplasty in young patients. We sought to characterize the re-revision-free survival and risk factors for re-revision in patients less than 55 years who underwent aseptic revision TKA. METHODS: We retrospectively reviewed 197 revision TKAs at a mean follow-up of 5 years. Mean age was 49 years; mean body mass index was 31 kg/m2. Twenty-seven (14%) patients had at least 1 prior revision TKA. The most common indications for revision included instability (29%), arthrofibrosis (26%), and aseptic loosening (24%). Constraint included the following: 59 posterior-stabilized (30%), 123 varus-valgus constrained (62%), and 15 hinged (8%). Components revised included the following: 93 femur/tibia (47%), 68 polyethylene-only (35%), 19 femur-only (10%), and 17 other (9%). Survivorship free from re-revision was calculated via the Kaplan-Meier method and a multivariate Cox proportional regression was utilized to identify risk factors for re-revision. RESULTS: Survivorship free from any re-revision at 5 years was 80%. In the multivariate analysis, patients with a prior revision (hazard ratio [HR] = 2.78, P = .02), an isolated polyethylene exchange (HR = 3.0, P = .004), and a hinged prosthesis (HR = 3.47, P = .05) were significant risk factors for lower revision-free survival. Forty-two patients (21%) underwent re-revision, most commonly for periprosthetic joint infection (7%), instability (6%), and aseptic loosening (5%). Re-revision occurred in 18/68 (26%) patients undergoing an isolated polyethylene exchange. CONCLUSION: Patients less than 55 years undergoing revision TKA have a modest 5-year revision-free survival of 80%. Patients with prior revision TKAs (HR = 2.78), hinge type prostheses (HR = 3.47), and polyethylene-only revisions (HR = 3.0) had higher revision rates.

Small soft tissue tension changes do not affect patient-reported outcomes one year after primary TKA.

BACKGROUND: Adequate soft tissue tension and balance is paramount to achieve favourable outcomes of total knee arthroplasty (TKA). Implant manufacturers offer 1-mm liner increments to fine-tune ligament tension and balance. In this study, we assessed if soft tissue tension changes introduced by minimal changes in liner thicknesses affect early patient reported outcomes. METHODS: Eighty-nine patients undergoing 99 primary, elective TKAs by a single surgeon were included. After achieving adequate ligament balance, the first 50 knees received an insert that would allow 2-3 mm of medial and lateral opening (control group), whereas the last 49 received an insert which was 1 mm thicker, resulting in a slight increase in ligament tension (study group). Sensor technology was used to record compartmental loads. Knee Society Score (KSS), KOOS Jr., and ROM were recorded pre-operatively, six weeks, four and 12 months post-operatively. The Forgotten Joint Score (FJS) was administered four and 12 months post-operatively. RESULTS: No differences were observed in demographic variables, pre-operative outcome scores, and ROM measures between groups. Six weeks post-operatively, there was no statistically significant difference in the outcome variables. Four months post-operatively, statistically significant differences were only observed in KOOS Jr. (79 and 73.6; p = 0.05), and FJS (59.9 and 45.5; p < 0.01); all of which favoured the control group. There was no difference in the outcome variables at 12 months. CONCLUSION: Minor changes in soft tissue tension induced by 1-mm changes in liner thickness resulted in clinically meaningful differences favouring the control group four months post-operatively, but in no clinically noticeable differences 12 months post-operatively. It is possible that lower soft tissue tension may lead to transient improvement in patient-reported early outcomes.

Dual Mobility Total Hip Arthroplasty Is Not Associated with a Greater Incidence of Groin Pain in Comparison with Conventional Total Hip Arthroplasty and Hip Resurfacing:A Retrospective Comparative Study.

BACKGROUND: Groin pain is a common long-term complication of total hip arthroplasty (THA). Femoral head size has been proposed as one of the primary causes. The implants used in dual mobility (DM) THA have large outer-bearing articulations, which could increase the risk of post-operative groin pain. Hip resurfacing (HR), too, has been shown to be associated with a risk of groin pain. QUESTIONS/PURPOSES: The goals of this study were to compare the incidence of groin pain at 1 year after hip arthroplasty in patients with different femoral head diameters and in patients undergoing conventional THA, DM THA, and HR. METHODS: After combing an institutional registry for all patients who had undergone THA or HR for primary hip osteoarthritis, we included 3193 patients in the analysis; 2008 underwent conventional THA, 416 underwent DM THA, and 769 underwent HR. We used logistic regression modeling to analyze the relation of groin pain at 1 year after surgery to patient demographics and clinical characteristics, including age, sex, body mass index (BMI), University of California at Los Angeles activity score at 1 year after surgery, bearing couple, and the ratio of acetabular diameter to femoral head diameter. We also measured cup inclination and anteversion in a subset of patients with and without groin pain at 1 year to assess whether pain could be related to implant position. RESULTS: Overall, 8.7% of patients reported groin pain at 1 year. Patients with groin pain were younger and had lower BMIs. There were increased odds of groin pain with a greater cup-to-head ratio, although DM implants, interestingly, were not significantly associated with groin pain; this may be attributable to so much of their movement taking place inside the implant. Subgroup analysis measuring cup inclination and anteversion showed no difference in cup position between patients with and without pain. CONCLUSION: In this population of hip arthroplasty patients, the incidence of groin pain 1 year after surgery did not differ among patients undergoing DM and conventional THA; DM THA in particular was not associated with a higher risk of groin pain, despite its comparatively larger femoral head sizes. HR, on the other hand, was associated with a higher risk of pain. Appropriate implant sizing and bearing couple choice may optimize the functional benefit of THA.

Aseptic Loosening at the Tibia in Total Knee Arthroplasty: A Function of Cement Mantle Quality?

BACKGROUND: Aseptic loosening remains one of the leading causes for failure of total knee arthroplasty (TKA). We sought to identify early radiographic measures that may associate with aseptic tibial component loosening, emphasizing systematic evaluation of the cement mantle. METHODS: All TKA revisions from 2007 to 2015 with the primary indication of tibial aseptic loosening were identified using in an institutional implant retrieval database. After exclusion criteria, 61 TKAs comprised the study group. A matched control group of 59 TKAs that had not failed at a minimum of 3 years was identified for comparison. Radiographic analysis on all 6-week postoperative radiographs included angulation of components, cement penetration depth, and presence of radiolucency at the implant-cement and bone-cement interfaces. Groups were compared with Student's t-test, chi-squared test, and Mann-Whitney U-test. A final multivariable logistic regression model was formed for the outcome of aseptic loosening. RESULTS: On multivariable analysis, failure was associated with a greater number of zones with cement penetration <2 mm (5.6 vs 3.4 zones, odds ratio [OR] 1.89, P < .001), increasing percent involvement of radiolucency at the implant-cement interface (8.7% vs 3.1%, OR = 1.15, P = .001), and increased varus alignment of the tibial component (1.5° vs 0°, OR = 1.35, P = .014). A greater number of zones with a radiolucent line at the bone-cement interface did not significantly associate (1.1 vs 0.3, P = .091). CONCLUSION: Our results suggest that radiographic indicators of poor cement mantle quality associate with later aseptic loosening. This emphasizes the need for surgeons to perform careful cement technique in order to reduce the risk of TKA failure. LEVEL OF EVIDENCE: III (Case-control).

Incidence and Risk Factors for Peripheral Nerve Injury After 383,000 Total Knee Arthroplasties Using a New York State Database (SPARCS).

BACKGROUND: Peripheral nerve injury (PNI) is a devastating complication following total knee arthroplasty (TKA). The purpose of this study is to identify risk factors for PNI after TKA using a New York Statewide Planning and Research Cooperative System. METHODS: The Statewide Planning and Research Cooperative System database was queried to identify patients who had undergone TKA from 1996 to 2014. Patient demographics, medical history, surgical details, hospital characteristics, and in-hospital complications were recorded. Cases in which a new unilateral PNI was identified were compiled, as were control cases. The characteristics of cases and controls underwent univariate testing and a multivariate logistic regression using Akaike information criterion model selection to identify risk factors for the development of PNI after TKA. RESULTS: In total, 383,060 cases were identified and 0.12%, or 445/383,060, experienced a new PNI. Pre-existing spinal conditions (odds ratio [OR] 1.98, confidence interval [CI] 1.08-3.30) and valgus deformity (OR 4.19, CI 2.46-6.66) were strongly correlated with the development of PNI postoperatively individually, but together increased risk substantially (OR 17.28, CI 2.83-55.35). Younger age (<50 years), in-hospital complications, female gender, and bilateral surgery were all associated with postoperative PNI, as well. CONCLUSION: Valgus deformity and previous spine disorder together greatly increased the risk of PNI after TKA. Younger age, female gender, and in-hospital postoperative complications all increased the risk of PNI, as well. This study quantifies the relative risk each of these factors impart in the development of PNI after TKA and can help healthcare providers and systems identify and counsel patients at higher risk of this serious complication.

Risk Factors for Peripheral Nerve Injury After 207,000 Total Hip Arthroplasties Using a New York State Database (Statewide Planning and Research Cooperative System).

BACKGROUND: Peripheral nerve injury (PNI) is a devastating complication following total hip arthroplasty (THA). The purpose of this study was to identify risk factors for PNI after THA using a New York Statewide Planning and Research Cooperative System (SPARCS). METHODS: The SPARCS database was queried to identify patients who had undergone THA from 1996 to 2011. Patient demographics, medical history, surgical details, hospital characteristics, and in-hospital complications were recorded. Cases in which a new unilateral PNI was identified were compiled, as were control cases in which a new PNI did not occur. The characteristics of cases and controls underwent univariate testing and a multivariate logistic regression using Akaike information criterion model selection to identify risk factors for the development of PNI after THA. RESULTS: 207,981 cases were identified, and 487 were coded as having a new PNI. Preexisting spinal conditions (odds ratio [OR] = 2.55, confidence interval [CI] = 1.61-3.83) were strongly correlated with the development of PNI postoperatively, as was dislocation (OR = 2.58, CI = 1.01-5.30) and diabetes with chronic complications (OR = 2.26, CI = 0.96-4.43). Younger age, in-hospital complications, and thromboembolic events were also associated with postoperative PNI. CONCLUSION: The incidence of PNI after THA was consistent with previous large-scale studies but may under-represent the true incidence because of undercoding inherent in large database studies. Previous spine disorder, chronic diabetes, younger age, and in-hospital postoperative complications all increased the risk of PNI. This study can help health-care providers and systems identify patients at higher risk of this serious complication.

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.

Discharge to Inpatient Rehab Does Not Result in Improved Functional Outcomes Following Primary Total Knee Arthroplasty.

BACKGROUND: Monitored rehabilitation has long been considered an essential part of the recovery process in total knee arthroplasty (TKA). However, the optimal setting for rehabilitation remains uncertain. We sought to determine whether inpatient rehabilitation settings result in improved functional and patient-reported outcomes after primary TKA. METHODS: All patients undergoing primary TKA from May 2007 to February 2011 were identified from our institutional total joint registry. Propensity score matching was then performed, resulting in a final cohort of 1213 matched pairs for discharge destination to either home or a rehabilitation facility (inpatient rehab or skilled nursing facility). Length of stay, need for manipulation, 6-month complications, and 2-year Western Ontario and McMaster Universities Osteoarthritis Index, Lower Extremity Activity Scale, 12-item Short Form Health Survey, and Hospital for Special Surgery knee expectations surveys were compared. RESULTS: Patients discharged to a rehab facility were noted to have a shorter hospital length of stay (5.0 vs 5.4 days). Patients discharged to inpatient rehabilitation reported more fractures at 6 months postoperatively. However, no differences in manipulation rates, 2-year outcome scores, or changes in outcome scores were found between the 2 groups. CONCLUSION: Inpatient rehabilitation settings did not result in lower complications at 6 months or improved functional or patient-reported outcomes at 2 years compared to discharge directly to home when patients are propensity matched for age, living situation, comorbidities, baseline functional status, and insurance status. This finding has important cost implications and calls into question whether the healthcare system should allow otherwise healthy patients to use inpatient rehabilitation services postoperatively after primary TKA.

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.

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.

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.