Does Approach Matter in Robotic-Assisted Total Hip Arthroplasty? A Comparison of Early Reoperations Between Direct Anterior and Postero-Lateral Approach.

BACKGROUND: There is no consensus on whether direct anterior approach (DAA) or postero-lateral approach (PLA) total hip arthroplasty (THA) confers a lower risk of postoperative complications. Robotic assistance in THA results in a more consistently accurate component position compared to manual THA. The objective of this study was to compare rates of dislocation, reoperation, revision, and patient-reported outcome measures between patients undergoing DAA and PLA robotic-assisted primary THA. METHODS: We identified 2,040 consecutive robotic-assisted primary THAs performed for primary osteoarthritis, using DAA (n = 497) or PLA (n = 1,542) between 2017 and 2020. The mean follow-up was 18 months. Kaplan-Meier analysis estimated survivorship free of dislocation, reoperation, and revision. Achievement of patient acceptable symptom state and minimum clinically important difference were used to compare changes in the Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS JR) and Visual Analog Scale. RESULTS: Dislocation was rare in this series (14 in 2,040, 0.7%), including 1 of 497 (0.2%) in the DAA cohort and 13 of 1,542 (0.8%) in the PLA cohort (P = .210). There was no difference in 2-year reoperation-free survivorship (97.8 versus 98.6%, P = .59) or revision-free survivorship (98.8 versus 99.0%, P = .87) at any time point. After controlling for age, sex, and body mass index, there was no difference in dislocation, reoperation, or revision. At 6-week follow-up, after controlling for age, sex, and body mass index, patients in the DAA cohort had higher odds of achieving HOOS JR minimum clinically important difference (odds ratio = 2.01, P = .012) and HOOS JR patient acceptable symptom state (odds ratio = 1.72, P = .028). There were no differences in patient-reported outcome measures by 3 months. CONCLUSIONS: For robotic-assisted primary THA, DAA may confer enhanced early (<6 weeks) functional recovery compared to the PLA, but there was no significant difference in postoperative dislocation, reoperation, or revision rates.

The John N. Insall Award: Does Melatonin Improve Subjective Sleep Quality After Total Knee Arthroplasty? A Randomized, Placebo-Controlled Trial.

BACKGROUND: Sleep disturbance is a common problem following total knee arthroplasty (TKA). The objective of this study was to determine if exogenous melatonin improves sleep quality following primary TKA. METHODS: A randomized, double-blind, placebo-controlled trial was conducted. A total of 172 patients undergoing unilateral TKA for primary knee osteoarthritis were randomized to receive either 5 mg melatonin (n = 86) or 125 mg vitamin C placebo (n = 86) nightly for 6 weeks. The primary outcome was the Pittsburgh Sleep Quality Index (PSQI) at 6 weeks and 90 days postoperatively. Secondary outcomes included 6-week and 90-day patient-reported outcome measures (PROMs), morphine milligram equivalents prescribed, medication compliance, adverse events, and 90-day readmissions. RESULTS: Mean PSQI scores worsened at 6 weeks before returning to the preoperative baseline at 90 days in both groups. There were no differences in PSQI scores between melatonin and placebo groups at 6 weeks (10.2 ± 4.2 versus 10.5 ± 4.4, P = .66) or 90 days (8.1 ± 4.1 versus 7.5 ± 4.0, P = .43). Melatonin did not improve the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Lower Extremity Activity Scale, Visual Analog Scale for pain, or Veterans Rand 12 Physical Component Score or Mental Component Score at 6 weeks or 90 days. Poor sleep quality was associated with worse PROMs at 6 weeks and 90 days on univariate and multivariable analyses, but melatonin did not modify these associations. There were no differences in morphine milligram equivalents prescribed, medication compliances, adverse events, or 90-day readmissions between both groups. CONCLUSIONS: Exogenous melatonin did not improve subjective sleep quality or PROMs at 6 weeks or 90 days following TKA. Poor sleep quality was associated with worse patient-reported function and pain. Our results do not support the routine use of melatonin after TKA.

Periprosthetic Joint Infection in Patients With Inflammatory Arthritis: Optimal Tests to Differentiate From Flares.

OBJECTIVE: Diagnosis of periprosthetic joint infection (PJI) in patients with inflammatory arthritis (IA) is challenging, as features of IA flares can mimic infection. We aimed to cross-sectionally determine if the optimal tests to diagnose PJI in osteoarthritis were present in patients with IA flares. METHODS: We enrolled patients from October 2020 to July 2022 in 3 groups: (a) PJI-total joint arthroplasty patients undergoing revision for infection, (b) IA Flare-IA patients with a flaring native joint, and (c) IA Aseptic-total joint arthroplasty patients with IA undergoing aseptic arthroplasty revision. We compared blood and synovial fluid markers between the cohorts using Kruskal-Wallis and Fisher exact tests to assess marker sensitivity and specificity. RESULTS: Of 52 cases overall, 40% had rheumatoid arthritis, 20% psoriatic arthritis, and 11% osteoarthritis (in PJI group). PJI cases had higher C-reactive protein (CRP) and synovial fluid polymorphonuclear neutrophil percentage (%PMN). Alpha-defensin tested positive in 93% of PJI cases, 20% of IA Flares, and 6% of IA Aseptic (p < 0.01). Synovial white blood cell count >3000/µL and positive alpha-defensin were highly sensitive (100%) in diagnosing infection; however, specificity was 50% for white blood cell counts and 79% for alpha-defensin. PJI diagnosis was nearly 5 times more likely with positive alpha-defensin and almost 6 times more likely with %PMNs >80. Blood markers interleukin-6, procalcitonin, and d-dimer were neither sensitive nor specific, whereas erythrocyte sedimentation rate and CRP showed 80% sensitivity, but 47% and 58% respective specificities. CONCLUSIONS: Although synovial %PMNs, CRP, and alpha-defensin are sensitive tests for diagnosing PJI, they are less specific and may be positive in IA flares.

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

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

Survivorship and Clinical Outcomes of Primary Total Knee Arthroplasty Performed in Patients 35 Years of Age and Younger.

BACKGROUND: Total knee arthroplasties (TKAs) for patients aged ≤35 years are rare but necessary for patients who have diseases such as juvenile idiopathic arthritis, osteonecrosis, osteoarthritis, and rheumatoid arthritis. Few studies have examined the 10-year and 20-year survivorship and clinical outcomes of TKAs for young patients. METHODS: A retrospective registry review identified 185 TKAs in 119 patients aged ≤ 35 years performed between 1985 and 2010 at a single institution. The primary outcome was implant survivorship free of revision. Patient-reported outcomes were assessed at 2 time points: 2011 to 2012 and 2018 to 2019. The average age was 26 years (range, 12 to 35). Mean follow-up was 17 years (range, 8 to 33). RESULTS: Survivorship decreased from 84% (95% confidence interval [CI]: 79 to 90) at 5 years to 70% (95% CI: 64 to 77) at 10 years and to 37% (95% CI: 29 to 45) at 20 years. The most common reasons for revision were aseptic loosening (6%) and infection (4%). Risk factors for revision included increasing age at time of surgery (Hazards Ratio [HR] 1.3, P = .01) and use of constrained (HR 1.7, P = .05) or hinged prostheses (HR 4.3, P = .02). There were 86% of patients reporting that their surgery resulted in "a great improvement" or better. CONCLUSION: Survivorship of TKAs in young patients is less favorable than expected. However, for the patients who responded to our surveys, TKA demonstrated substantial pain relief and improvement in function at 17-year follow-up. Revision risk increased with older age and higher levels of constraint.

Wound Complications Are Affected by Different Skin Closure Methods in Primary Hip and Knee Arthroplasty.

BACKGROUND: There is a lack of consensus on optimal skin closure and dressing strategies to reduce early wound complication rates after primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: All 13,271 patients at low risk for wound complications undergoing primary, unilateral THA (7,816), and TKA (5,455) for idiopathic osteoarthritis at our institution between August 2016 and July 2021 were identified. Skin closure, dressing type, and postoperative events related to wound complications were recorded during the first 30 postoperative days. RESULTS: The need for unscheduled office visits to address wound complications was more frequent after TKA than THA (2.74 versus 1.78%, P < .001), and after direct anterior versus posterior approach THA (2.94 versus 1.39%, P < .001). Patients who developed a wound complication, had a mean of 2.9 additional office visits. Compared to the use of topical adhesives, skin closure with staples had the highest risk of wound complications (odds ratio 1.8 [1.07-3.11], P = .028). Topical adhesives with polyester mesh had higher rates of allergic contact dermatitis than topical adhesives without mesh (1.4 versus 0.5%, P < .0001). CONCLUSION: Wound complications after primary THA and TKA were often self-limited but increased burden on the patient, surgeon, and care team. These data, which suggest different rates of certain complications with different skin closure strategies, can inform a surgeon on optimal closure methods in their practice. Adoption of the skin closure technique with the lowest risk of complications in our hospital would conservatively result in a reduction of 95 unscheduled office visits and save a projected $585,678 annually.

Outcomes After Revision Total Knee Arthroplasty From a Specific, Now-Recalled Implant System.

BACKGROUND: A specific total knee arthroplasty (TKA) implant system was recently recalled for high incidence of early polymeric wear and osteolysis. We analyzed the early outcomes of aseptic revision with these implants. METHODS: We identified 202 aseptic revision TKAs of this implant system performed at a single institution between 2010 and 2020. Revision indications included aseptic loosening (n = 120), instability (n = 55), and polymeric wear/osteolysis (n = 27). Components were revised in 145 cases (72%) and isolated polyethylene insert exchange occurred in 57 cases (28%). Kaplan-Meier and Cox proportional hazards analyses were used to determine survivorship free from all-cause rerevision and rerevision risk factors. RESULTS: At 2 and 5 years, survivorship free from all-cause rerevision was 89 and 76% in the polyethylene exchange cohort versus 92 and 84% in the component revision cohort (P = .5). At 2 and 5 years, survivorship in revision with components from the same manufacturer was 89 and 80% compared to 95 and 86% in revision with components from a different manufacturer (P = .2). Among re-revisions (n = 30), cones (37%), sleeves (7%), hinge/distal femoral replacement implants were frequently used (13%). Men had increased risk for rerevision (hazard ratio = 2.3, P = .04). CONCLUSION: In this series of aseptic revision TKAs performed on a now-recalled implant system, survivorship free from rerevision was lower than expected when components from the same manufacturer were utilized, but comparable to contemporary reports when both the components were revised with an alternative implant system. Metaphyseal fixation with cones and sleeves as well as highly constrained implants was frequently utilized at time of rerevision TKA. LEVEL OF EVIDENCE: Level IV.

2023 American College of Rheumatology and American Association of Hip and Knee Surgeons Clinical Practice Guideline for the Optimal Timing of Elective Hip or Knee Arthroplasty for Patients With Symptomatic Moderate-to-Severe Osteoarthritis or Advanced Symptomatic Osteonecrosis With Secondary Arthritis for Whom Nonoperative Therapy Is Ineffective.

OBJECTIVE: To develop evidence-based consensus recommendations for the optimal timing of hip and knee arthroplasty to improve patient-important outcomes including, but not limited to, pain, function, infection, hospitalization, and death at 1 year for patients with symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis of the hip or knee who have previously attempted nonoperative therapy, and for whom nonoperative therapy was ineffective, and who have chosen to undergo elective hip or knee arthroplasty (collectively referred to as TJA). METHODS: We developed 13 clinically relevant population, intervention, comparator, outcomes (PICO) questions. After a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to rate the quality of evidence (high, moderate, low, or very low), and evidence tables were created. A Voting Panel, including 13 physicians and patients, discussed the PICO questions until consensus was achieved on the direction (for/against) and strength (strong/conditional) of the recommendations. RESULTS: The panel conditionally recommended against delaying TJA to pursue additional nonoperative treatment including physical therapy, nonsteroidal antiinflammatory drugs, ambulatory aids, and intraarticular injections. It conditionally recommended delaying TJA for nicotine reduction or cessation. The panel conditionally recommended delay for better glycemic control for patients who have diabetes mellitus, although no specific measure or level was identified. There was consensus that obesity by itself was not a reason for delay, but that weight loss should be strongly encouraged, and the increase in operative risk should be discussed. The panel conditionally recommended against delay in patients who have severe deformity or bone loss, or in patients who have a neuropathic joint. Evidence for all recommendations was graded as low or very low quality. CONCLUSION: This guideline provides evidence-based recommendations regarding the optimal timing of TJA in patients who have symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis for whom nonoperative therapy was ineffective to improve patient-important outcomes, including pain, function, infection, hospitalization, and death at 1 year. We acknowledge that the evidence is of low quality primarily due to indirectness and hope future research will allow for further refinement of the recommendations.

History of COVID-19 infection is not associated with increased D-dimer levels and risk of deep-vein thrombosis in total joint arthroplasty.

INTRODUCTION: In the acute phase of COVID-19, elevated D-dimer levels indicate a hypercoagulable state putting the patients at increased risk for venous thromboembolic disease (VTE). It is unclear, if prior COVID-19 disease increases the risk for VTE after total joint arthroplasty (TJA) and if D-dimer levels can be used to identify patients at risk. MATERIALS AND METHODS: D-Dimer levels of 313 consecutive SARS-CoV-2 IgG-positive and 2,053 -negative patients undergoing TJA between 05/20 and 12/20 were evaluated. D-Dimer levels were divided into three groups: < 200 ng/ml, 200-400 ng/ml, and > 400 ng/ml D-dimer units (DDU). 277 SARS-CoV-2 IgG-positive patients underwent a Doppler ultrasound to rule out deep-vein thrombosis (DVT) 4-6 weeks after TJA. RESULTS: D-Dimer levels did not differ significantly between SARS-CoV-2 IgG-positive and -negative patients (p value 0.53). Among SARS-CoV-2 IgG-negative patients, 1687 (82.17%) had D-dimer levels < 200 ng/ml, 256 (12.47%) between 200 and 400 ng/ml, and 110 (5.36%) > 400 ng/ml. Of the SARS-CoV-2 IgG-positive patients, 257 (83.71%) had D-dimer levels < 200 ng/ml, 34 (11.07%) between 200 and 400 ng/ml, and 16 (5.21%) > 400 ng/ml. A postoperative DVT was detected in nine patients (2.9%) in the SARS-CoV-2 IgG-positive group and a PE in one patient (0.3%). 7/229 patients with < 200 ng/ml (3.1%), 1/28 patients (3.6%) with 200-400 ng/ml and 1/9 patients (11.1%) with D-dimer levels > 400 ng/ml had a DVT or PE (p = 0.43). CONCLUSIONS: The findings of this investigation suggest there is no difference in D-dimer levels between SARS-CoV-2 IgG-positive and -negative patients undergoing TJA. Although there is a trend for increased VTE rates with increased D-dimer levels, routine D-dimer testing is not recommended based on the current data. SARS-CoV-2 IgG-positive patients have a low risk of VTE in the current study.

Survivorship and Risk Factors for Re-Revision after Aseptic Revision Total Hip Arthroplasty in Patients Aged ≤55 Years.

BACKGROUND: There is a relative paucity of literature on the outcomes after revision total hip arthroplasty (rTHA) in young patients. This study reports the survivorship and risk factors for re-revision in patients aged ≤55 years. METHODS: We identified 354 patients undergoing aseptic nononcologic rTHA at mean follow-up of 5 years after revision, with mean age of 48 years, body mass index of 28 kg/m2, and 64% female. Thirty-five (10%) patients underwent at least 1 previous rTHA. The main indications for rTHA included wear/osteolysis (21%), adverse local tissue reaction (21%), recurrent instability (20%), acetabular loosening (16%), and femoral loosening (7%); and included acetabular component-only rTHA in 149 patients (42%), femoral component-only rTHA in 46 patients (13%), both component rTHA in 44 patients (12%), and head/liner exchanges in patients 115 (33%). The Kaplan-Meier method was used to measure survivorship free from re-revision THA, and multivariate regression was used to identify risk factors for re-revision THA. RESULTS: Sixty-two patients (18%) underwent re-revision THA at the mean time of 2.5 years, most commonly for instability (37%), aseptic loosening (27%), and prosthetic joint infection (15%). The rTHA survivorship from all-cause re-revision and reoperation was 83% and 79% at 5 years, respectively. Multivariate analysis demonstrated that patients undergoing femoral component only (hazard ratio 4.8, P = .014) and head/liner exchange rTHA (hazard ratio 2.5, P = .022) as risk factors for re-revision THA. CONCLUSION: About 1 in 5 patients aged ≤55 years undergoing rTHA required re-revision THA at 5 years, most commonly for instability. The highest risk group included patients undergoing head/liner exchanges and isolated femoral component revisions.

Contemporary Distal Femoral Replacements for Supracondylar Femoral Fractures Around Primary and Revision Total Knee Arthroplasties.

BACKGROUND: There is a paucity of data on the outcomes of distal femoral replacements (DFRs) in patients with total knee arthroplasty (TKA) periprosthetic fractures. We sought to characterize these patients' survivorship free from rerevision. METHODS: We retrospectively identified 49 patients, including 34 after primary TKA (primary cohort), 9 after revision TKA, and 6 conversions for failed open reduction and internal fixation (revision cohort) that underwent DFR for a periprosthetic femur fracture. The mean age was 76 years, and 40 patients (82%) were female. The mean follow-up was 4 years. Femoral fixation included 44 cemented stems (90%) and 5 cementless stems (10%). Survivorship free from rerevision was characterized by the Kaplan-Meier method; cox proportional regression was used to analyze the risk factors for rerevision. RESULTS: Survivorship free from any rerevision at 5 years in the primary and revision cohort was 93% and 18%, respectively. The revision cohort had a 5.3× higher risk of re-revision (P = .008). Survivorship free from re-revision for aseptic loosening at 5 years in the primary and revision cohort was 93% and 53%, respectively. Two of the 3 patients with cementless stems in the primary cohort underwent early rerevision for aseptic loosening, but patients with prior primary TKAs treated with cemented femoral fixation (n = 31) had a 97% 5-year survivorship free from re-revision. CONCLUSION: Patients with periprosthetic fractures around prior primary TKAs treated with DFRs with cemented femoral fixation had a 97% 5-year survivorship free from any re-revision. DFRs for periprosthetic femur fractures around revision TKAs or conversions of failed open reduction and internal fixations have a 5× increased risk of rerevision.

High Satisfaction and Activity Levels After Total Hip Arthroplasty in Patients Under Age 21.

BACKGROUND: With improved materials and bearing surfaces, the use of total hip arthroplasty (THA) in young patients is increasing. Functional outcomes and activity level are particularly relevant in this higher-demand patient population. There is a paucity of data on patient-reported outcomes and activity levels after THA in extremely young (<21 years old) patients. METHODS: We identified 196 patients (222 hips) who underwent THA at age <21 years at our institution from 1982 to 2018. After applying exclusion criteria, 113 of 160 (70.6%) patients (129 hips) were available for follow-up. Patient activity levels and functional outcomes were evaluated using the UCLA activity score, Forgotten Joint Score (FJS), Hip Disability and Osteoarthritis Outcome Score for Joint Replacement, and a validated 5-question satisfaction survey. Survivorship and reasons for revision were recorded. RESULTS: The mean age at surgery was 17.0 ± 2.8 years, and the mean follow-up was 13.2 years (range 2-38 years). The most common indications for THA were osteonecrosis (34%) and juvenile idiopathic arthritis (30%). The mean UCLA activity score was 5.9 ± 2.0, and 64% of patients reported a score ≥6. The mean FJS was 57.9 ± 31.0. The mean Hip Disability and Osteoarthritis Outcome Score for Joint Replacement score was 84.6 ± 16.6. Ninety percent of patients reported that they were very or somewhat satisfied with their surgery. At final follow-up, 27 of 129 (20.9%) hips had undergone revision surgery. CONCLUSION: THA performed in patients under 21 years of age with end-stage hip disease allows for high levels of activity and satisfaction postoperatively, with most patients being able to participate in moderate recreational activities. These data may be useful for surgeons in planning for and counseling extremely young patients indicated for THA.

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.

Periprosthetic Femur Fractures After Total Hip Arthroplasty: Does the Mode of Failure Correlate With Classification?

BACKGROUND: Periprosthetic femur fracture is one of the most common indications for reoperation after total hip arthroplasty. Our objectives were to evaluate the incidence of reoperation after the surgical treatment of periprosthetic femur fractures and to compare the mechanisms of failure between fractures around a stable femoral component and those with an unstable femoral component. METHODS: We identified a consecutive series of 196 surgically treated periprosthetic fractures after total hip arthroplasty between 2008 and 2017. Mean age was 72 years (range, 29-96 years), and 108 (55%) were women. The femoral component was unstable in 127 cases (65%) and stable in the remaining 69 cases (35%). Mean follow-up was 2 years. RESULTS: The 2-year cumulative probability of any reoperation was 19%. The most common indication for reoperation among the cases with a stable femoral component was nonunion, and the most common indication for reoperation among the cases with an unstable femoral component was infection. Fractures that originated at the distal aspect of the femoral component were associated with a high risk of nonunion (6 of 28 cases, P < .01) and reoperation (9 of 28 cases, P = .03). CONCLUSION: Surgeons should take measures to mitigate the failure modes that are distinct based on fracture type. The high infection rate after surgical management of B2 fracture suggests that additional antiseptic precautions may be warranted. For B1 fractures, particularly those originating near the distal aspect of the femoral component, augmenting fixation with orthogonal plating, spanning the entire femur, or revising the stem in cases of poor proximal bone should be considered.

Prior Knee Arthroscopy Is Associated With Increased Risk of Revision After Total Knee Arthroplasty.

BACKGROUND: Knee arthroscopy (KA) is frequently performed to provide improved joint function and pain relief. However, outcomes following total knee arthroplasty (TKA) after prior KA are not fully understood. The purpose of this study is to determine the relationship between prior KA within 2 years of TKA on revision rates after TKA. METHODS: Data were collected from the Humana insurance database using the PearlDiver Patient Records Database from 2006 to 2017. Subjects were identified using Current Procedural Terminology and International Classification of Diseases procedure codes to identify primary TKA. Patients were stratified into 2 groups based upon a history of prior KA. Univariate and multivariate analyses were conducted to determine association between KA and outcomes at 2-year postoperative period. RESULTS: In total, 138,019 patients were included in this study, with 3357 (2.4%) patients receiving a KA before TKA and 134,662 (97.6%) patients who did not. The most common reason for KA was osteoarthritis (40.0%), followed by medial tear of the meniscus (26.0%) and chondromalacia (21%.0). After adjustment, prior KA was associated with increased revision rate (odds ratio [OR], 1.392; P = .003), postoperative stiffness (OR, 1.251; P = .012), periprosthetic joint infection (OR, 1.326; P < .001), and aseptic loosening (OR, 1.401; P = .048). CONCLUSION: Prior KA is significantly associated with increased 2-year TKA revision rate. The most common etiology for arthroscopy was osteoarthritis. The results of the study, showing that arthroscopy before TKA substantially increases the rates of revision, PJI, aseptic loosening, and stiffness, lend further credence to the idea that patients may be better served by nonsurgical management of their degenerative pathology until they become candidates for TKA. Subjecting this population to arthroscopy appears to offer limited benefit at the cost of poorer outcomes when they require arthroplasty in the future. LEVEL OF EVIDENCE: Level III therapeutic study.

Conversion of Hip Resurfacing With Retention of Monoblock Acetabular Shell Using Dual-Mobility Components.

BACKGROUND: Retention of the acetabular component is an option during conversion from hip resurfacing arthroplasty (HRA) to total hip arthroplasty (THA). The purpose of this study was to compare clinical outcomes of conversion of the femoral resurfacing component with retained acetabular components (RAC) and use of dual-mobility femoral heads to outcomes of patients treated with both component (BC) revisions. METHODS: A retrospective review was performed of the clinical outcomes of HRA to THA conversions performed at a single institution between 2008 and 2017. RESULTS: Seventy-one conversions were included (27 RAC and 44 BC). Average age at time of conversion was 54.4 years (range, 30-68 years). Median time to conversion was 5.14 (2.77-7.41) years and median follow-up post-conversion was 1.7 (0.33-4.0) years. There were no significant differences in indications for conversion between the 2 groups with the majority performed for complications related to elevated metal ions and aseptic loosening. Harris Hip Scores improved from pre-conversion to post-conversion in both cohorts (P < .01). There were no significant differences in pre-conversion and post-conversion metal ion levels between the RAC and BC groups. Serum metal ion levels decreased significantly in both cohorts (P < .01). There were 6 additional revisions in the cohort (4 in BC, 2 in RAC) at a median 2.94 (1.99-3.85) years post-conversion. Two RAC patients had intraprosthetic dislocations with extensive polyethylene wear requiring acetabular revision at median 3.92 (3.85-3.98) years post-conversion. Overall, there were a higher number of complications in the BC group related to acetabular fracture, failure of osseointegration, and periprosthetic joint infection; however, this did not reach statistical significance (P = .27). CONCLUSION: Salvage of an appropriately positioned, well-fixed HRA acetabular component is a reasonable option in the setting of conversion to THA using dual-mobility components. This technique avoids the morbidity of acetabular revision and was associated with a decrease in metal ion levels and improvements in short-term functional outcomes comparable to a BC revision.

Improving Estimates of Annual Survival Rates for Medial Unicompartmental Knee Arthroplasty, a Meta-Analysis.

BACKGROUND: Medial unicompartmental knee arthroplasty (mUKA) is an increasingly popular treatment option for medial compartment knee osteoarthritis. Published mUKA survival rates have varied. The purpose of this meta-analysis was to provide pooled estimates of mUKA survival 5 and 10 years postoperatively. METHODS: We included studies in English within the last 15 years with a clear description of mUKA failure. Random-effects models were used to pool complementary log-log transformed implant survival estimates at 5 and 10 years postoperatively. Between-study variance was estimated using the restricted maximum likelihood method. Between-study heterogeneity was tested using the χ2 test and quantified using the I2 statistic. I2 values <25%, 25%-75%, and >75% were considered low, moderate, and high, respectively. Multivariable meta-regression was used to assess the potential association of mean patient age and study start year with survival estimates at 5 and 10 years. All analyses were performed using the metafor and meta packages implemented in R software version 3.3.4 (R Foundation for Statistical Computing, Vienna, Austria). RESULTS: Twenty-six studies met inclusion criteria, representing 42,791 knees. Study-level and pooled 5- and 10-year mUKA survival estimates were 95.3% (95% confidence interval, 93.6-96.6) and 91.3% (88.9-93.3), respectively. Between-study heterogeneity was high (>88%) for all years. Mean patient age and study start year explained only 12.3% and 30.7% of between-study heterogeneity at 5 and 10 years, respectively. CONCLUSION: Five- and 10-year pooled mUKA survival estimates were 95.3% and 91.3%, respectively. These data establish better estimates of mUKA survivorship and can help when counseling patients considering mUKA.

Diagnosing Prosthetic Joint Infections in Patients With Inflammatory Arthritis: A Systematic Literature Review.

BACKGROUND: Patients with inflammatory arthritis (IA) are at increased risk of prosthetic joint infections (PJI), yet differentiating between septic and aseptic failure is a challenge. The aim of our systematic review is to evaluate synovial biomarkers and their efficacy at diagnosing PJI in patients with IA. METHODS: A comprehensive literature search was performed in the following databases from inception to January 2018: Ovid MEDLINE, Ovid EMBASE, and the Cochrane Library. Searches across the databases retrieved 367 results. Two of 5 reviewers independently screened a total of 298 citations. Discrepancies were resolved by a third reviewer. Twenty articles fit our criteria, but due to methodological differences findings could not be pooled for meta-analysis. For 5 studies, raw data were provided, pooled, and used to derive optimal diagnostic cut points. RESULTS: Our final analysis included 1861 non-IA patients, including 426 patients with PJI, and 90 IA patients of whom 26 had PJI. There was a significant difference among the 4 groups for serum C-reactive protein (CRP), erythrocyte sedimentation rate, and synovial CRP, polymorphonuclear neutrophil percent, white blood cells, interleukin (IL)-6, IL-8, and IL-1b. Polymorphonuclear neutrophil percent had the highest sensitivity (95.2%) and specificity (85.0%) to detect infections with an optimum threshold of 78%. CONCLUSION: While levels of synovial white blood cells, IL-6, IL-8, and serum CRP appear higher in patients with IA, there is overlap with those who are not infected. Further studies are needed to explore diagnostic tests that will better detect PJI in patients with IA.

Comparison of Expectations and Outcomes in Rheumatoid Arthritis Versus Osteoarthritis Patients Undergoing Total Knee Arthroplasty.

BACKGROUND: We hypothesized that patients undergoing primary total knee arthroplasty (TKA) for rheumatoid arthritis (RA) would have different preoperative expectations compared to osteoarthritis (OA) patients, and that postoperative satisfaction would correlate with specific postoperative pain and functional domains. METHODS: This is a retrospective cohort study of RA patients matched based on age, gender, American Society of Anesthesiologists score, and Charlson Comorbidity Index score 1:2 with OA patients (76 RA, 152 OA) who underwent primary TKA. The Hospital for Special Surgery Knee Replacement Expectations Survey, Visual Analogue Scale for Pain (VAS), Knee injury and Osteoarthritis Outcome Score (KOOS), and the Short Form-12 (SF-12) were compared at baseline and at 2 years postoperatively. Minimum clinically important differences (MCIDs) were calculated for KOOS and SF-12 subdomains. RESULTS: Preoperatively, RA patients had lower expectations, worse VAS Pain, and worse KOOS Pain, Symptoms, and Activities of Daily Living (P < .05). However, at 2 years, RA patients had significantly larger improvements in VAS (P = .01) and these 3 KOOS subdomains (P < .05), achieving comparable absolute scores to OA patients. Overall, 86.1% of RA and 87.1% of OA patients were either somewhat or very satisfied with their TKA. Patient satisfaction correlated with VAS Pain and KOOS outcome scores in both groups. RA and OA patients had high rates of achieving MCID in SF-12 physical component scores and all 5 KOOS subdomains. A higher proportion of RA patients achieved MCID in KOOS Symptoms (98.4% vs 77.2%, P < .001). CONCLUSION: RA patients had lower baseline expectations compared to OA patients. However, RA patients had greater improvements in KOOS and SF-12 subdomains, and there was no difference in satisfaction compared to OA patients after TKA.