Single-cell Transcriptome Analysis Identifies Senescent Osteocytes as Contributors to Bone Destruction in Breast Cancer Metastasis.

Breast cancer bone metastases increase fracture risk and are a major cause of morbidity and mortality among women. Upon colonization by tumor cells, the bone microenvironment undergoes profound reprogramming to support cancer progression that disrupts the balance between osteoclasts and osteoblasts, leading to bone lesions. Whether such reprogramming affects matrix-embedded osteocytes remains poorly understood. Here, we demonstrate that osteocytes in breast cancer bone metastasis develop premature senescence and a distinctive senescence-associated secretory phenotype (SASP) that favors bone destruction. Single-cell RNA sequencing identified osteocytes from mice with breast cancer bone metastasis enriched in senescence and SASP markers and pro-osteoclastogenic genes. Using multiplex in situ hybridization and AI-assisted analysis, we detected osteocytes with senescence-associated distension of satellites, telomere dysfunction, and p16Ink4a expression in mice and patients with breast cancer bone metastasis. In vitro and ex vivo organ cultures showed that breast cancer cells promote osteocyte senescence and enhance their osteoclastogenic potential. Clearance of senescent cells with senolytics suppressed bone resorption and preserved bone mass in mice with breast cancer bone metastasis. These results demonstrate that osteocytes undergo pathological reprogramming by breast cancer cells and identify osteocyte senescence as an initiating event triggering bone destruction in breast cancer metastases.

Robotic Total Knee Arthroplasty Surgeon Marketing: Do Claims Align With the Literature?

Background: Robotic total knee arthroplasty (R-TKA) utilization and marketing continue to rise. We examined the marketing on surgeon websites regarding R-TKA benefits and sought to determine if the claims were supported by existing literature. Methods: A Google search identified 10 physician websites from each of the 5 largest U.S. markets by population with the term "robotic total knee arthroplasty city, state." Claims on websites about R-TKA were categorized. Literature from 2012-2022 was reviewed for data "for" or "against" each claim. Level of evidence for each publication was collected. Results: Fifty websites were captured that included 59 surgeons. A specific R-TKA platform was mentioned on 68% of websites. Website claims about robotics were placed into 8 major categories. Literature review supported the claims of more precise/accurate, reduced injury to tissue, and less pain with more literature "for" than "against" the claims. Conclusions: Claims made on physician websites regarding the benefits of R-TKA are variable and not definitively supported by existing literature. Most available data can be categorized into levels of evidence III, IV, and V. There is a paucity of level I evidence to support the various marketing statements. Physicians should be cognizant of both the claims made on their websites and the literature that could be used to support or refute those specific claims.

Successful Transition to Same Calendar Day Discharge in Total Joint Arthroplasty at an Academic Center.

Background: There has been a shift toward same-day discharge (SDD) in total joint arthroplasty (TJA) in recent years. Our clinical standard had been next-day discharge, but the COVID pandemic led to a hospital bed shortage, causing us to shift to SDD directly from the Post-Anesthesia Care Unit (PACU). The aim of our project was to investigate if the SDD protocol was successful and if it changed complications or 90-day readmission rates. Our secondary aim was to investigate if the protocol created disparities in patient selection. Methods: A retrospective review compared the first 100 patients intended to discharge from PACU to the 100 patients prior to the SDD protocol undergoing elective primary TJA procedures at our academic institution from September 1, 2020, to March 23, 2021. The SDD protocol started on November 19, 2020. Results: During this SDD period, 98% (98/100) of patients were successfully discharged from the PACU. The 90-day readmission rate changed from 0% to 2% (P = .4975), and the overall complication rate changed from 2% to 5% (P = .4448). Most complications were manipulation under anesthesia to improve range of motion. Manipulations under anesthesia changed from 1% to 4% (P = .3687). Conclusions: The transition to same SDD in TJA at our academic institution was successfully implemented without markedly increasing complications, readmissions, or changing patient selection. The COVID-19 pandemic likely influenced the recovery of patients before and after the protocol. Future studies are needed to validate this data during the post-COVID era.

Do Quality Measures or Hospital Characteristics Predict Readmission Penalties for Hip and Knee Arthroplasty?

BACKGROUND: Quality rating systems exist to grade the value of care provided by hospitals, but the extent to which these rating systems correlate with patient outcomes is unclear. The association of quality rating systems and hospital characteristics with excess readmission penalties for total hip arthroplasty (THA) and total knee arthroplasty (TKA) was studied. METHODS: The fiscal year 2022 Inpatient Prospective Payment System final rule was used to identify 2,286 hospitals subject to the Hospital Readmissions Reduction Program. Overall, 6 hospital quality rating systems and 5 hospital characteristics were obtained. These factors were analyzed to determine the effect on hospital penalties for THA and TKA excess readmissions. RESULTS: Hospitals that achieved a higher Medicare Overall Hospital Quality Star Rating demonstrated a significantly lower likelihood of receiving THA and TKA readmission penalties (Cramer's V = 0.236 and Rp = -0.233; P < .001 for both). Hospitals ranked among the US News & World Report's top 50 best hospitals for orthopaedics were significantly less likely to be penalized (V = 0.042; P = .043). The remaining 4 quality rating systems were not associated with readmission penalties. Penalization was more likely for hospitals with fewer THA and TKA discharges (Rp = -0.142; P < .001), medium-sized institutions (100 to 499 beds; V = 0.075; P = .002), teaching hospitals (V = 0.049; P = .019), and safety net hospitals (V = 0.043; P = .039). Penalization was less likely for West and Midwest hospitals (V = 0.112; P < .001). CONCLUSIONS: A higher Overall Hospital Quality Star Rating and recognition among the US News & World Report's top 50 orthopaedic hospitals were associated with a reduced likelihood of THA and TKA readmission penalties. The other 4 widely accepted quality rating systems did not correlate with readmission penalties. Teaching and safety net hospitals may be biased toward higher readmission rates.

The Chitranjan S. Ranawat Award: Manipulation Under Anesthesia to Treat Postoperative Stiffness After Total Knee Arthroplasty: A Multicenter Randomized Clinical Trial.

BACKGROUND: Manipulation under anesthesia (MUA) occurs in 4% of patients after total knee arthroplasty (TKA). Anti-inflammatory medications may target arthrofibrosis pathogenesis, but the data are limited. This multicenter randomized clinical trial investigated the effect of adjuvant anti-inflammatory medications with MUA and physical therapy on range of motion (ROM) and outcomes. METHODS: There were 124 patients (124 TKAs) who developed stiffness after primary TKA for osteoarthritis enrolled across 15 institutions. All received MUA when ROM was < 90° at 4 to 12 weeks postoperatively. Randomization proceeded via a permuted block design. Controls received MUA and physical therapy, while the treatment group also received one dose of pre-MUA intravenous dexamethasone (8 mg) and 14 days of oral celecoxib (200 mg). The ROM and clinical outcomes were assessed at 6 weeks and 1 year. This trial was registered with ClinicalTrials.gov. RESULTS: The ROM significantly improved a mean of 46° from a pre-MUA ROM of 72 to 118° immediately after MUA (P < .001). The ROM was similar between the treatment and control groups at 6 weeks following MUA (101 versus 99°, respectively; P = .35) and at one year following MUA (108 versus 108°, respectively; P = .98). Clinical outcomes were similar at both end points. CONCLUSIONS: In this multicenter randomized clinical trial, the addition of intravenous dexamethasone and a short course of oral celecoxib after MUA did not improve ROM or outcomes. However, MUA provided a mean ROM improvement of 46° immediately, 28° at 6 weeks, and 37° at 1 year. Further investigation in regards to dosing, duration, and route of administration of anti-inflammatory medications remains warranted. LEVEL OF EVIDENCE: Level 1, RCT.

A NOTCH3-CXCL12-driven myeloma-tumor niche signaling axis promotes chemoresistance in multiple myeloma.

Multiple myeloma (MM) remains incurable due to disease relapse and drug resistance. Notch signals from the tumor microenvironment (TME) confer chemoresistance, but the cellular and molecular mechanisms are not entirely understood. Using clinical and transcriptomic datasets, we found that NOTCH3 is upregulated in CD138+ cells from newly diagnosed MM (NDMM) patients compared to healthy individuals and increased in progression/relapsed MM (PRMM) patients. Further, NDMM patients with high NOTCH3 expression exhibited worse responses to Bortezomib (BOR)-based therapies. Cells of the TME, including osteocytes, upregulated NOTCH3 in MM cells and protected them from apoptosis induced by BOR. NOTCH3 activation (NOTCH3OE) in MM cells decreased BOR anti-MM efficacy and its ability to improve survival in in vivo myeloma models. Molecular analyses revealed that NDMM and PRMM patients with high NOTCH3 exhibit CXCL12 upregulation. TME cells upregulated CXCL12 and activated the CXCR4 pathway in MM cells in a NOTCH3-dependent manner. Moreover, genetic or pharmacologic inhibition of CXCL12 in NOTCH3OE MM cells restored sensitivity to BOR regimes in vitro and in human bones bearing NOTCH3OE MM tumors cultured ex vivo. Our clinical and preclinical data unravel a novel NOTCH3-CXCL12 pro-survival signaling axis in the TME and suggest that osteocytes transmit chemoresistance signals to MM cells.

Kinematic Performance of Medial Pivot Total Knee Arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) implants have continued to evolve to accommodate new understandings of knee mechanics. The medial-pivot implant is a newer design, which is intended to limit anterior-posterior translation in the medial compartment while allowing lateral compartment translation. However, evidence for a generalized medial-pivot characteristic across all activities is limited. The purpose of the study was to quantify and compare in vivo knee joint kinematics using high-speed stereo radiography during activities of daily living in patients who have undergone a TKA with a cruciate sacrificing medial-pivot implant to age-matched and sex-matched native controls. METHODS: Fifteen participants (7 patients, 4 women, mean age 70 years and 8 nonsymptomatic controls, 4 women, mean age 64 years) performed 6 functional tasks in high-speed stereo radiography: deep-knee lunge, chair rise, step down, gait, gait with 90° turn, and seated knee extension. Translational differences between groups (surgical versus control) were assessed for the medial and lateral condyle, while pivot location was normalized to subject-specific tibial plateau geometry. RESULTS: The surgical cohort displayed a more constrained medial condyle that provided greater stability of the medial compartment and did not result in the paradoxical anterior translation at mid-flexion angles during weight-bearing activities, but was associated with less condylar translation than native knees. Additionally, the transverse tibial pivot location occurs most commonly in the middle third of the tibial plateau and secondarily on the medial third. CONCLUSIONS: Some variability in pivot location occurs between activities and is more in nonsymptomatic, native knee controls.

Simulation training to retool practicing orthopedic surgeons is rare.

Purpose: Modern surgical practice is continuously changing as technology develops. New techniques are often implemented after a surgeon has made the transition to independent clinical practice. There is therefore a need to 'retool' technical skills. Additionally, practicing surgeons must maintain and develop skills such as leadership, communication, critical thinking, teaching, and mentoring. Our aim was to perform a scoping review to assess the current status of simulation education for practicing Orthopedic Surgeons (OS). Methods: A 10 year search of PubMed, ERIC, and Web of Science was performed with a medical librarian. Controlled vocabulary Medical Subject Headings terms and natural language were developed with subject matter experts describing simulation, training and OS. Two trained reviewers evaluated all abstracts for inclusion. Exclusion criteria were articles that did not assess simulation education involving practicing OS. Data were extracted from the included full text articles by two reviewers: details of study design, type of participants, type of simulation and role of OS in the educational event. Results: Initial search identified 1824 articles of which 443 were duplicates, and 1381 articles were further screened. Of these, 1155 were excluded, 226 full text articles were assessed for eligibility and 80 included in analysis. Most were published in the last 6 years and from the United States. The majority (99%) described technical skill simulations (arthroscopy 56%, screw placement 23%, ligament reconstruction 19%). OS were rarely the only learners with 91% studies also having residents participate. OS were the targeted learner in 6% studies. OS provided content validity for 15 (19%) and construct validity in 59 (74%) studies. Conclusions: Simulation training to educate practicing OS is rare. OS are often used to validate work rather than being the center of an educational endeavor. A refocusing is needed to provide adequate training for practicing surgeons to retool skills as new techniques become available.

Current status of virtual reality simulation education for orthopedic residents: the need for a change in focus.

Introduction: Advances in technology are changing surgical education. Simulation provides an important adjunct to operative experience. This pedagogy has arguably become more important in light of the COVID-19 pandemic, with resultant reduction in operative exposure for trainees. Virtual reality (VR) simulators may provide significant contribution to experiential learning; however, much of the investigative focus to date has, correctly, been on establishing validity evidence for these constructs. The aim of this work was to perform a scoping review to assess the current status of VR simulation education to determine curricular development efforts for orthopedic residents. Methods: With a trained medical librarian, searches of PubMed, EMBASE, and Web of Science were conducted for all articles in the last 10 years (September 2011-September 2021). Controlled vocabulary Medical Subject Headings (MeSH) terms and natural language developed with subject matter experts describing virtual reality or VR simulation and orthopedic training were used. Two trained reviewers evaluated all abstracts for inclusion. Exclusion criteria were all articles that did not assess VR simulation education involving orthopedic residents. Data were extracted from the included full-text articles including: study design, type of participants, type of VR simulation, simulated orthopedic skill, type of educational event, learner assessment including Kirkpatrick's level, assessment of quality using the Medical Education Research Study Quality Instrument (MERSQI), and level of effectiveness (LoE). Results: Initial search identified 1,394 articles, of which 61 were included in the final qualitative synthesis. The majority (54%) were published in 2019- 2021, 49% in Europe. The commonest VR simulator was ArthroS (23%) and the commonest simulated skill was knee arthroscopy (33%). The majority of studies (70%) focused on simulator validation. Twenty-three studies described an educational module or curriculum, and of the 21 (34%) educational modules, 43% were one-off events. Most modules (18/21, 86%) assessed learners at Kirkpatrick level 2. With regard to methodological quality, 44% of studies had MERSQI 11.5-15 and 89% of studies had LoE of 2. Two studies had LoE of 3. Conclusion: Current literature pertaining to VR training for orthopedic residents is focused on establishing validity and rarely forms part of a curriculum. Where the focus is education, the majority are discrete educational modules and do not teach a comprehensive amalgam of orthopedic skills. This suggests focus is needed to embed VR simulation training within formal curricula efforts guided by the work of Kern, and assess the efficacy of these against patient outcomes.

Postoperative Opioid Consumption is Greater after Simultaneous versus Staged Bilateral Total Knee Arthroplasty.

Increased exposure to opioids around total knee arthroplasty (TKA) can lead to a risk of long-term dependence. We hypothesized that performing simultaneous bilateral total knee arthroplasty (simBTKA) over staged surgery (staged bilateral total knee arthroplasty [stgBTKA]) may decrease the total amount of opiates used. We retrospectively reviewed 29 patients who underwent simBTKAs performed between February 2015 and November 2020 and identified 23 that did not use opioids ≤90 days prior to surgery. These were frequency matched for gender and body mass index to 50 stgBTKAs completed within 6 months who also were opioid-free ≤90 days prior to their first surgery. Using our state's prescription database, we reviewed postsurgery opioid refills and morphine milligram equivalents (MMEs) for the two groups and compared their initial MME prescription at discharge and their total MME consumption 6 months postoperatively. Total MME consumption for the stgBTKA group included all prescriptions following the first and 6 months after the second surgery, whereas for the simBTKA group, total consumption included the 6 months after their two same-day surgeries. The simBTKA group had more MMEs prescribed initially (median = 375) than did the stgBTKA group after second surgery (median = 300; p < 0.007), larger postoperative-refill MMEs in the first 30 days (median = 300) than stgBTKA (median = 0; p = 0.221) and increased total MME consumption 6 months after surgery (median = 675) compared with stgBTKA after second surgery (median = 450; p = 0.077). However, both groups had similar monthly consumptions rates, with medians I MMEs/month of 112 for simBTKA versus 96 for stgBTKA (p = 0.585). Our results suggest there is no significant difference in opioid consumption between simBTKA and stgBTKA. In fact, we found that simBTKA patients received larger opioid amounts in the immediate postoperative period as well as slightly larger amounts at 30 days.

Lower Body Joint Moments during the Golf Swing in Older Adults: Comparison to Other Activities of Daily Living.

Golf participation has increased dramatically in the last several years. With this increase in participation, clinicians need better evidenced based strategies to advise those golfers with different pathologies when it is safe to return to the game. Golf teaching professionals also need to understand how to alter golf mechanics to protect injured and/or diseased joints in golfers to allow them to play pain free and avoid further injury. This study used a 3-dimensional link segment model to calculate the net joint moments on the large lower limb joints (knee and hip) during golf (lead and trail leg) and two commonly studied activities of daily living (gait and sit-to-stand) in 22 males, healthy, adult golfers. It also examined the correlations between these knee and hip joint loads and club head speed. The external valgus knee moment and the internal hip adduction moment were greater in the lead leg in golf than in the other activities and were also correlated with club head speed. This indicates a strategy of using the frontal plane GRF moment during the swing. The internal hip extension and knee flexion moment were also greater in the golf swing as compared with the other activities and the hip extension moment was also correlated with club head speed. This emphasizes the importance of hip extensor (i.e., gluteus maximus and hamstring) muscle function in golfers, especially in those emphasizing the use of anterior-posterior ground reaction forces (i.e., the pivoting moment). The golf swing places some loads on the knee and the hip that are much different than the loads during gait and sit-to-stand tasks. Knowledge of these golf swing loads can help both the clinician and golf professional provide better evidence-based advice to golfers in order to keep them healthy and avoid future pain/injury.

Articulating Hip Spacers with a Constrained Acetabular Liner: Effect of Acetabular Bone Loss and Cementation Quality.

Articulating hip spacers for periprosthetic joint infection (PJI) offer numerous advantages over static spacers such as improved patient mobilization, hip functionality, and soft tissue tension. Our study aimed to determine complication rates of a functional articulating spacer using a constrained liner to determine the role of acetabular cementation mantle and bone loss on the need for second-stage surgery. A retrospective review of 103 patients was performed and demographic information, spacer components and longevity, spacer-related complications, reinfection rates, and grade of bone loss and acetabular cement mantle quality were determined. There was no significant difference in spacer-related complications or reinfection rate between PJI and native hip infections. 33 of 103 patients (32.0%) elected to retain their spacers. Between patients who retained their initial spacer and those who underwent reimplantation surgery, there was not a significant difference in cement mantle grade (p = 0.52) or degree of bone loss (p = 0.78). Functional articulating antibiotic spacers with cemented constrained acetabular liners demonstrate promising early results in the treatment of periprosthetic and native hip infections. The rate of dislocation events was low. Further efforts to improve cement fixation may help decrease the need for second-stage reimplantation surgery.

Reduced osteoprotegerin expression by osteocytes may contribute to rebound resorption after denosumab discontinuation.

Denosumab is an anti-RANKL Ab that potently suppresses bone resorption, increases bone mass, and reduces fracture risk. Discontinuation of denosumab causes rapid rebound bone resorption and bone loss, but the molecular mechanisms are unclear. We generated humanized RANKL mice and treated them with denosumab to examine the cellular and molecular conditions associated with rebound resorption. Denosumab potently suppressed both osteoclast and osteoblast numbers in cancellous bone in humanized RANKL mice. The decrease in osteoclast number was not associated with changes in osteoclast progenitors in bone marrow. Long-term, but not short-term, denosumab administration reduced osteoprotegerin (OPG) mRNA in bone. Localization of OPG expression revealed that OPG mRNA is produced by a subpopulation of osteocytes. Long-term denosumab administration reduced osteocyte OPG mRNA, suggesting that OPG expression declines as osteocytes age. Consistent with this, osteocyte expression of OPG was more prevalent near the surface of cortical bone in humans and mice. These results suggest that new osteocytes are an important source of OPG in remodeling bone and that suppression of remodeling reduces OPG abundance by reducing new osteocyte formation. The lack of new osteocytes and the OPG they produce may contribute to rebound resorption after denosumab discontinuation.

Clinical utility of mesenchymal stem/stromal cells in regenerative medicine and cellular therapy.

Mesenchymal stem/stromal cells (MSCs) have been carefully examined to have tremendous potential in regenerative medicine. With their immunomodulatory and regenerative properties, MSCs have numerous applications within the clinical sector. MSCs have the properties of multilineage differentiation, paracrine signaling, and can be isolated from various tissues, which makes them a key candidate for applications in numerous organ systems. To accentuate the importance of MSC therapy for a range of clinical indications, this review highlights MSC-specific studies on the musculoskeletal, nervous, cardiovascular, and immune systems where most trials are reported. Furthermore, an updated list of the different types of MSCs used in clinical trials, as well as the key characteristics of each type of MSCs are included. Many of the studies mentioned revolve around the properties of MSC, such as exosome usage and MSC co-cultures with other cell types. It is worth noting that MSC clinical usage is not limited to these four systems, and MSCs continue to be tested to repair, regenerate, or modulate other diseased or injured organ systems. This review provides an updated compilation of MSCs in clinical trials that paves the way for improvement in the field of MSC therapy.

Inconsistency and Ambiguity Within the International Classification of Disease 10 Procedure Coding System for Hip Fractures.

BACKGROUND: The International Statistical Classification of Diseases (ICD), 10th Revision Procedure Coding System (PCS) was created to increase the granularity of procedural coding. These codes are entered by hospital coders from information derived from the medical record. Concern exists that this increase in complexity could lead to inaccurate data. METHODS: Medical records and ICD-10-PCS codes were reviewed for operatively treated geriatric hip fractures from January 2016 through February 2019 at a tertiary referral medical center. Definitions for each of the 7-unit figures from the 2022 American Medical Association's ICD-10-PCS official codebook were compared to the medical, operative, and implant records. RESULTS: There were 56% (135 of 241) of PCS codes that had ambiguous, partially incorrect, or frankly incorrect figures within the code. One or more inaccurate figures were noted in 72% (72 of 100) of fractures treated with arthroplasty compared to 44.7% (63 of 141) treated with fixation (P < .01). There was at least 1 frankly incorrect figure contained in 9.5% (23 of 241) of codes. Approach was coded ambiguously for 24.8% (29 of 117) of pertrochanteric fractures. Device/implant codes were partially incorrect in 34.9% (84 of 241) of all hip fracture PCS codes. Hemi and total hip arthroplasties were partially incorrect in 78.4% (58 of 74) and 30.8% (8/26) of device/implant codes, respectively. Significantly more femoral neck (69.4%, 86 of 124) than pertrochanteric fractures (41.9%, 49 of 117) had 1 or more incorrect or partially correct figures (P < .01). CONCLUSION: Despite the increased granularity of ICD-10-PCS codes, the application of this system is inconsistent and often incorrect when applied to hip fracture treatments. The definitions in the PCS system are difficult to be utilized by coders and do not reflect the operation performed.

Practice Changes Induced by a Traveling Fellowship.

The John N. Insall Knee Society Traveling Fellowship selects four international arthroplasty or sports fellowship-trained orthopaedic surgeons to spend 1 month traveling to various Knee Society members' joint replacement and knee surgery centers in North America. The fellowship aims to foster research and education and shares ideas among fellows and Knee Society members. The role of such traveling fellowships on surgeon preferences has yet to be investigated. A 59-question survey encompassing patient selection, preoperative planning, intraoperative techniques, and postoperative protocols was completed by the four 2018 Insall Traveling Fellows before and immediately after the completion of traveling fellowship to assess anticipated practice changes (e.g., initial excitement) related to their participation in a traveling fellowship. The same survey was completed 4 years after the completion of the traveling fellowship to assess the implementation of the anticipated practice changes. Survey questions were divided into two groups based on levels of evidence in the literature. Immediately after fellowship, there was a median of 6.5 (range: 3-12) anticipated changes in consensus topics and a median of 14.5 (range: 5-17) anticipated changes in controversial topics. There was no statistical difference in the excitement to change consensus or controversial topics (p = 0.921). Four years after completing a traveling fellowship, a median of 2.5 (range: 0-3) consensus topics and 4 (range: 2-6) controversial topics were implemented. There was no statistical difference in the implementation of consensus or controversial topics (p = 0.709). There was a statistically significant decline in the implementation of changes in consensus and controversial preferences compared with the initial level of excitement (p = 0.038 and 0.031, respectively). After the John N. Insall Knee Society Traveling Fellowship, there is excitement for practice change in consensus and controversial topics related to total knee arthroplasty. However, few practice changes that had initial excitement were implemented after 4-year follow-up. Ultimately, the effects of time, practice inertia, and institutional friction overcome most of the anticipated changes induced by a traveling fellowship.

Surgical Approach Does Not Affect Chronic Opioid Usage After Total Hip Arthroplasty.

BACKGROUND: Three different surgical approaches (the direct anterior, antero-lateral, and posterior) are commonly used for total hip arthroplasty (THA). Due to an internervous and intermuscular approach, the direct anterior approach may result in less postoperative pain and opioid use, although all 3 approaches have similar outcomes 5 years after surgery. Perioperative opioid medication consumption poses a dose-dependent risk of long-term opioid use. We hypothesized that the direct anterior approach is associated with less opioid usage over 180 days after surgery than the antero-lateral or posterior approaches. METHODS: A retrospective cohort study was performed including 508 patients (192 direct anterior, 207 antero-lateral, and 109 posterior approaches). Patient demographics and surgical characteristics were identified from the medical records. The state prescription database was used to determine opioid use 90 days before and 1 year after THA. Regression analyses controlling for sex, race, age, and body mass index were used to determine the effect of surgical approach on opioid use over 180 days after surgery. RESULTS: No difference was seen in the proportion of long-term opioid users based on approach (P = .78). There was no significant difference in the distribution of opioid prescriptions filled between surgical approach groups in the year after surgery (P = .35). Not taking opioids 90 days prior to surgery, regardless of approach, was associated with a 78% decrease in the odds of becoming a chronic opioid user (P < .0001). CONCLUSION: Opioid use prior to surgery, rather than THA surgical approach, was associated with chronic opioid consumption following THA.

Extensor Mechanism Disruption Remains a Challenging Problem.

BACKGROUND: Extensor mechanism disruption (EMD) following total knee arthroplasty (TKA) is a devastating problem commonly treated with allograft or synthetic reconstruction. Understanding of reconstruction success rates and patient recorded outcomes is lacking. METHODS: Patients who have an EMD after TKA undergoing mesh or whole-extensor allograft reconstruction between 2011 and 2019, with minimum 2-year follow-up were reviewed at two tertiary care centers. Functional failure was defined as extensor lag >30 degrees, amputation, or fusion, as well as revision extensor mechanism reconstruction (EMR). Survivorship was assessed using Kaplan-Meier curves, and factors for success were determined with logistic regressions. RESULTS: Of fifty-six EMRs (49 patients), 50.0% (28/56) were functionally successful at 3.2 years of mean follow-up (range, 0.2 to 7.4). In situ survivorship of the reconstructions at 36 months was 75.0% (42 of 58). There were 50.0% (14 of 28) of functionally failed EMRs that retained their reconstruction at last follow-up. Mean extensor lag among successes and failures was 5.4 and 71.0° (P = .01), respectively. Mean Knee Injury and Osteoarthritis Outcome Score, Joint Replacement scores were 67.1 and 48.8 among successes and failures (P = .01). There were 64.0% (16 of 25) of successes and 1 of 19 failures that obtained a Knee Injury and Osteoarthritis Outcome Score, Joint Replacement score above the minimum patient-acceptable symptom state for TKA. Survivorship and success rates were similar between reconstruction methods (P = .86; P = .76). All-cause mortality was 8.2% (4 of 49), each with EMR failure prior to death. All-cause reoperation rate was 42.9% (24 of 56), with a 14.3% (8 of 56) rate of revision EMR and 10.7% (6 of 56) rate of above-knee-amputation or modular fusion. CONCLUSIONS: This multicenter investigation of mesh or allograft EMR demonstrated modest functional success at 3.2 years. Complication and reoperation rates were high, regardless of EMR technique. Therefore, EMD after TKA remains problematic.

Articulating Knee Spacers in the Treatment of Periprosthetic Joint Infection: All Polyethylene Tibia or Tibial Insert?

BACKGROUND: The best antibiotic spacer for periprosthetic knee joint infection treatment is unknown. Using a metal-on-polyethylene (MoP) component provides a functional knee and may avoid a second surgery. Our study investigated complication rates, treatment efficacies, durabilities, and costs of MoP articulating spacer constructs using either an all-polyethylene tibia (APT) or a polyethylene insert (PI). We hypothesized that while the PI would cost less, the APT spacer would have lower complication rates and higher efficacies and durabilities. METHODS: A retrospective review evaluated 126 consecutive articulating knee spacer (64 APTs and 62 PIs) cases from 2016 to 2020 was performed. Demographic information, spacer components, complication rates, infection recurrence, spacer longevity, and implant costs were analyzed. Complications were classified as follows: spacer-related; antibiotic-related; infection recurrence; or medical. Spacer longevity was measured for patients who underwent reimplantation and for those who had a retained spacer. RESULTS: There were no significant differences in overall complications (P < .48), spacer-related complications (P = 1.0), infection recurrences (P = 1.0), antibiotic-related complications (P < .24), or medical complications (P < .41). Average time to reimplantation was 19.1 weeks (4.3 to 98.3 weeks) for APT spacers and 14.4 weeks (6.7 to 39.7 weeks) for PI spacers (P = .09). There were 31% (20 of 64) of APT spacers and 30% (19 of 62) of PI spacers that remained intact for an average duration of 26.2 (2.3 to 76.1) and 17.1 weeks (1.7 to 54.7) (P = .25), respectively, for patients who lived for the duration of the study. PI spacers cost less than APT ($1,474.19 versus $2,330.47, respectively; P < .0001). CONCLUSION: APT and PI tibial components have similar results regarding complication profiles and infection recurrence. Both may be durable if spacer retention is elected, with PI constructs being less expensive.

Radiographic Findings in Flexion Instability after Total Knee Arthroplasty.

Flexion instability (FI) is one of the leading causes of knee pain and revision surgery. Generally, the biomechanical etiology is considered to be a larger flexion than extension gap. This may be due to mismatch of components sizes to the bone or malalignment. Other factors such as muscle weakness may also play a role, and the diagnosis of FI after total knee arthroplasty (TKA) relies on a combination of patient's complaints during stair descent or walking and physical examination findings. Our study examines the role of implant positioning and sizes in the diagnosis of FI. A retrospective review of 20 subjects without perceived FI and 13 patients diagnosed with FI after TKA was conducted. Knee injury and osteoarthritis outcome scores (KOOS) were documented, and postoperative radiographs were examined. Measurements including included tibial slope, condylar offset, femoral joint line elevation along with surrogate soft-tissue measures for girth and were compared between groups. The FI group was found to have a significantly lower KOOS score compared with the non-FI group (55.6 vs. 73.5; p = 0.009) as well as smaller soft-tissue measurements over the pretubercle region (6.0 mm vs. 10.6 mm; p = 0.007). Tibial slope, condylar offset ratios, and femoral joint line elevation were not significantly different between the FI and non-FI groups. We noted a significant difference in tibial slope in posterior-stabilized implants in subjects with and without FI (6.4° vs. 1.5°; p = 0.003). Radiographic measurements consistent with malalignment were not indicative of FI. X-ray measurements alone are not sufficient to conclude FI as patient symptoms, and clinical examinations remain the key indicators for diagnosis. Radiographic findings may aid in surgeon determination of an underlying cause for an already identified FI situation and help in planning revision surgery.