Revealing a Natural Model of Pre-Osteoarthritis of the Hip Through Study of Femoroacetabular Impingement.

Femoroacetabular impingement (FAI) is considered the mechanical cause of hip osteoarthritis (OA). Surgical intervention involves labrum repair and osteochondroplasty to remove the impingement, alleviating symptoms. Nevertheless, some patients progress to hip OA after surgery, indicating that factors other than mechanical abnormality are contributing to hip OA progression. This review article discusses our laboratory's studies on hip FAI and OA, undertaken to identify key molecular players in the progression of hip OA. Transcriptome analysis identified peroxisome proliferator activated receptor gamma (PPARγ) as a crucial molecule in early hip OA. PPARγ, widely expressed in chondrocytes, has a protective role in preventing OA, but its true mechanism remains unknown. We observed a dysregulation of DNA methyltransferase (DNMT) in the progression of hip OA, with high expression of DNMT1 and 3A and downregulation of DNMT3B. Moreover, we established that DNMT3A is the main molecule that is binding to PPARγ promoter CpG area, and hypermethylation of this area occurs during disease progression. This suggests that epigenetic changes are a main mechanism that regulates PPARγ expression. Finally, we developed a novel rabbit model of hip FAI and OA and are currently performing studies to validate our small-animal model to human FAI.

PROMIS Physical Function and Pain Interference Scores Correlate with the Lower Extremity Toronto Extremity Salvage Score.

The Toronto Extremity Salvage Score (TESS) and the National Institutes of Health Patient-Reported Outcomes Measurement Information System (PROMIS) are both utilized to measure patient-reported outcomes in adults with musculoskeletal oncologic conditions. However, the relationship between them has not been studied. We sought to describe a link between Lower Extremity (LE) TESS and PROMIS Physical Function (PF) scores, as well as between LE TESS and Pain Interference (PI) scores, to develop a method for converting scores between TESS and PROMIS and to examine whether TESS and PROMIS captured differences in pain and function between clinically relevant subgroups in our population. Methods: Our study population consisted of 125 adult patients who underwent surgical treatment of a lower-extremity musculoskeletal tumor at a single sarcoma center between December 2015 and October 2018. The LE TESS questionnaire was administered to patients via paper and the PROMIS PF and PI were administered via iPad at a preoperative appointment. The relationship between LE TESS and PROMIS measures was analyzed with use of generalized linear modeling. Subgroup analyses were performed with a 2-tailed t test or 1-way analysis of variance. Results: PROMIS PF had a very strong positive correlation with LE TESS (r = 0.83) and was related through the following equation: PROMIS PF = 0.00294 × (LE TESS)2 + 22.6. PROMIS PI had a strong negative correlation with LE TESS (r = -0.77) and was related through the following equation: PROMIS PI = -0.00259 × (LE TESS)2 + 73.8. PROMIS PF and PI performed similarly to LE TESS across multiple patient subgroups and captured the expected differences between subgroups. Conclusions: LE TESS and PROMIS PF appeared to measure similar information in patients with an orthopaedic oncologic condition. Moreover, PROMIS PI scores were strongly correlated with functional disability as measured with the LE TESS. Understanding the relationship between TESS and PROMIS will allow the comparison and combination of data for both clinical and research purposes. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Did the Physical and Mental Health of Orthopaedic Patients Change After the Onset of the COVID-19 Pandemic?

BACKGROUND: The 2019 novel coronavirus (COVID-19) pandemic has been associated with poor mental health outcomes and widened health disparities in the United States. Given the inter-relationship between psychosocial factors and functional outcomes in orthopaedic surgery, it is important that we understand whether patients presenting for musculoskeletal care during the pandemic were associated with worse physical and mental health than before the pandemic's onset. QUESTIONS/PURPOSES: (1) Did patients seen for an initial visit by an orthopaedic provider during the COVID-19 pandemic demonstrate worse physical function, pain interference, depression, and/or anxiety than patients seen before the pandemic, as measured by the Patient-Reported Outcomes Measurement Information System (PROMIS) instrument? (2) During the COVID-19 pandemic, did patients living in areas with high levels of social deprivation demonstrate worse patterns of physical function, pain interference, depression, or anxiety on initial presentation to an orthopaedic provider than patients living in areas with low levels of social deprivation, compared with prepandemic PROMIS scores? METHODS: This was a retrospective, comparative study of new patient evaluations that occurred in the orthopaedic department at a large, urban tertiary care academic medical center. During the study period, PROMIS computer adaptive tests were routinely administered to patients at clinical visits. Between January 1, 2019, and December 31, 2019, we identified 26,989 new patients; we excluded 4% (1038 of 26,989) for being duplicates, 4% (1034 of 26,989) for having incomplete demographic data, 44% (11,925 of 26,989) for not having a nine-digit home ZIP Code recorded, and 5% (1332 of 26,989) for not completing all four PROMIS computer adaptive tests of interest. This left us with 11,660 patients in the "before COVID-19" cohort. Between January 1, 2021 and December 31, 2021, we identified 30,414 new patients; we excluded 5% (1554 of 30,414) for being duplicates, 4% (1142 of 30,414) for having incomplete demographic data, 41% (12,347 of 30,414) for not having a nine-digit home ZIP Code recorded, and 7% (2219 of 30,414) for not completing all four PROMIS computer adaptive tests of interest. This left us with 13,152 patients in the "during COVID-19" cohort. Nine-digit home ZIP Codes were used to determine patients' Area Deprivation Indexes, a neighborhood-level composite measure of social deprivation. To ensure that patients included in the study represented our overall patient population, we performed univariate analyses on available demographic and PROMIS data between patients included in the study and those excluded from the study, which revealed no differences (results not shown). In the before COVID-19 cohort, the mean age was 57 ± 16 years, 60% (7046 of 11,660) were women, 86% (10,079 of 11,660) were White non-Hispanic, and the mean national Area Deprivation Index percentile was 47 ± 25. In the during COVID-19 cohort, the mean age was 57 ± 16 years, 61% (8051 of 13,152) were women, 86% (11,333 of 13,152) were White non-Hispanic, and the mean national Area Deprivation Index percentile was 46 ± 25. The main outcome measures in this study were the PROMIS Physical Function ([PF], version 2.0), Pain Interference ([PI], version 1.1), Depression (version 1.0), and Anxiety (version 1.0). PROMIS scores follow a normal distribution with a mean t-score of 50 and a standard deviation of 10. Higher PROMIS PF scores indicate better self-reported physical capability, whereas higher PROMIS PI, Depression, and Anxiety scores indicate more difficulty managing pain, depression, and anxiety symptoms, respectively. Clinically meaningful differences in PROMIS scores between the cohorts were based on a minimum clinically important difference (MCID) threshold of 4 points. Multivariable linear regression models were created to determine whether presentation to an orthopaedic provider during the pandemic was associated with worse PROMIS scores than for patients who presented before the pandemic. Regression coefficients (ß) represent the estimated difference in PROMIS scores that would be expected for patients who presented during the pandemic compared with patients who presented before the pandemic, after adjusting for confounding variables. Regression coefficients were evaluated in the context of clinical importance and statistical significance. Regression coefficients equal to or greater than the MCID of 4 points were considered clinically important, whereas p values < 0.05 were considered statistically significant. RESULTS: We found no clinically important differences in baseline physical and mental health PROMIS scores between new patients who presented to an orthopaedic provider before the COVID-19 pandemic and those who presented during the COVID-19 pandemic (PROMIS PF: ß -0.2 [95% confidence interval -0.43 to 0.03]; p = 0.09; PROMIS PI: ß 0.06 [95% CI -0.13 to 0.25]; p = 0.57; PROMIS Depression: ß 0.09 [95% CI -0.14 to 0.33]; p = 0.44; PROMIS Anxiety: ß 0.58 [95% CI 0.33 to 0.84]; p < 0.001). Although patients from areas with high levels of social deprivation had worse PROMIS scores than patients from areas with low levels of social deprivation, patients from areas with high levels of social deprivation demonstrated no clinically important differences in PROMIS scores when groups before and during the pandemic were compared (PROMIS PF: ß -0.23 [95% CI -0.80 to 0.33]; p = 0.42; PROMIS PI: ß 0.18 [95% CI -0.31 to 0.67]; p = 0.47; PROMIS Depression: ß 0.42 [95% CI -0.26 to 1.09]; p = 0.23; PROMIS Anxiety: ß 0.84 [95% CI 0.16 to 1.52]; p = 0.02). CONCLUSION: Contrary to studies describing worse physical and mental health since the onset of the COVID-19 pandemic, we found no changes in the health status of orthopaedic patients on initial presentation to their provider. Although large-scale action to mitigate the effects of worsening physical or mental health of orthopaedic patients may not be needed at this time, orthopaedic providers should remain aware of the psychosocial needs of their patients and advocate on behalf of those who may benefit from intervention. Our study is limited in part to patients who had the self-agency to access specialty orthopaedic care, and therefore may underestimate the true changes in the physical or mental health status of all patients with musculoskeletal conditions. Future longitudinal studies evaluating the impact of specific COVID-19-related factors (for example, delays in medical care, social isolation, or financial loss) on orthopaedic outcomes may be helpful to prepare for future pandemics or natural disasters. LEVEL OF EVIDENCE: Level II, prognostic study.

A Novel Model of Hip Femoroacetabular Impingement in Immature Rabbits Reproduces the Distinctive Head-Neck Cam Deformity.

BACKGROUND: Femoroacetabular impingement (FAI) is a leading cause of hip pain in young adults and often leads to degenerative osteoarthritis (OA). A small animal model of hip deformities is crucial for unraveling the pathophysiology of hip OA secondary to FAI. PURPOSES: To (1) characterize a new minimally invasive surgical technique to create a proximal femoral head-neck deformity in a skeletally immature rabbit model and (2) document the effect of an injury to the medial proximal femoral epiphysis on head-neck morphology at 28 days after the injury. STUDY DESIGN: Controlled laboratory study. METHODS: Six-week-old New Zealand White rabbits (n = 10) were subjected to right hip surgery, with the left hip used as a control. An epiphyseal injury in the medial femoral head was created using a 1.6-mm drill. Hips were harvested bilaterally at 28 days after surgery. Alpha and epiphyseal shaft angles were measured on radiographs. Alpha angles at the 1- and 3-o'clock positions were measured on the oblique axial plane of micro-computed tomography images. Bone bar formation secondary to growth plate injuries was confirmed using alcian blue hematoxylin staining. RESULTS: All hips in the study group showed a varus-type head-neck deformity, with lower epiphyseal shaft angles on anteroposterior radiographs versus those in the control group (133°± 8° vs 142°± 5°, respectively; P = .022) and higher epiphyseal shaft angles on lateral radiographs (27°± 12° vs 10°± 7°, respectively; P < .001). The mean alpha angles in the study group were higher at both the 1- (103°± 14° vs 46°± 7°, respectively; P < .002) and 3-o'clock (99°± 18° vs 35°± 11°, respectively; P < .002) positions than those in the control group. Alcian blue hematoxylin staining of all hips in the study group indicated that the injured physis developed a bony bar, leading to growth plate arrest on the medial femoral head. CONCLUSION: The proposed model led to growth arrest at the proximal femoral physis, resulting in a femoral head-neck deformity similar to human FAI. CLINICAL RELEVANCE: Our novel small animal model of a femoral head-neck deformity is a potential platform for research into the basic mechanisms of FAI disease progression and the development of disease-modifying therapies.

Isolation and Culture of Periosteum-Derived Progenitor Cells from Mice.

This chapter describes the methods of isolation of mouse periosteal progenitor cells. There are three basic methods utilized. The bone grafting method was developed utilizing the fracture healing process to expand the progenitor populations. Bone capping methods requires enzymatic digestion and purification of cells from the native periosteum, while the Egression/Explant method requires the least manipulation with placement of cortical bone fragments with attached periosteum in a culture dish. Various cell surface antibodies have been employed over the years to characterize periosteum derived progenitor cells, but the most consistent minimal criteria was recommended by the International Society for Cellular Therapy. Confirmation of the multipotent status of these isolated cells can be achieved by differentiation into the three basic mesodermal lineages in vitro.

FoxO1 is a crucial mediator of TGF-ß/TAK1 signaling and protects against osteoarthritis by maintaining articular cartilage homeostasis.

Transforming growth factor-ß (TGF-ß) signaling is a critical regulator for articular cartilage tissue maintenance and chondrocyte homeostasis. Nonetheless, the regulatory networks and downstream signaling pathways that govern the chondroprotective function of TGF-ß in the context of osteoarthritis (OA) are not fully defined. Recent studies reveal that mice with postnatal deletion of triple forkhead box class Os (FoxOs) (1, 3, and 4) spontaneously develop OA-like pathologies. The OA phenotype largely recapitulates that observed in mice with loss of TGF-ßR2. In the present study, we investigated the role of FoxOs as downstream mediators of TGF-ß signaling and define their role in articular cartilage homeostasis. Among the three FoxOs (1, 3, and 4), TGF-ß signaling exclusively regulates FoxO1 in a TGF-ß activated kinase 1 (TAK1)-dependent manner. Furthermore, FoxO1 was genetically ablated in mice in a tissue-specific manner in articular cartilage or overexpressed in adult cartilage immediately followed by meniscal/ligament injury (MLI). Histological and microcomputed tomography (micro-CT) analyses demonstrated that loss of FoxO1 postnatally in articular cartilage leads to OA-like pathologies, and gain of FoxO1 in adult cartilage has both preventative and therapeutic effects on surgically induced OA. Mechanistically, FoxO1 was found to maintain articular chondrocyte homeostasis through induction of anabolic and autophagy-related gene expressions. Importantly, overexpression of FoxO1 markedly rescued the OA phenotypes caused by deficiency in TGF-ß signaling in chondrocytes. Our study identifies that TGF-ß/TAK1-FoxO1 is a key signaling cascade in regulation of articular cartilage autophagy and homeostasis and is a potentially important therapeutic target for OA-like joint diseases.

Distinct Pattern of Inflammation of Articular Cartilage and the Synovium in Early and Late Hip Femoroacetabular Impingement.

BACKGROUND: The molecular mechanism of how femoroacetabular impingement (FAI) morphology leads to hip osteoarthritis (OA) is yet to be determined. The expression and location of inflammation-related molecules during early- and late-stage FAI have not been previously described. Moreover, the characterization of intra-articular inflammation away from the cam deformity as well as the nature of adjacent synovial tissue have also not been extensively reported. HYPOTHESIS: Early-stage FAI has a similar expression of inflammation-related markers in the head-neck and acetabular cartilage but less synovitis than late-stage FAI. STUDY DESIGN: Controlled laboratory study. METHODS: Head-neck cartilage, acetabular cartilage, and synovial samples were obtained from patients undergoing hip preservation surgery for the treatment of symptomatic cam FAI (early FAI group; n = 15) and advanced OA secondary to cam FAI (late FAI group; n = 15). Samples procured from healthy young adult donors served as the control group (n = 7). Cartilage degeneration was assessed by histology, and the expression of inflammation-related proteins (interleukin-1 beta [IL-1ß], matrix metalloproteinase-13 [MMP-13], a disintegrin and metalloproteinase with thrombospondin motifs-4 [ADAMTS-4], type II collagen [COL2], and aggrecan neoepitope [NITEGE]) was measured by immunostaining. Synovial samples in the early and late FAI groups were examined for synovitis and the expression of IL-1ß. RESULTS: Head-neck cartilage in the early FAI group showed significantly more degeneration than the control group and an increased expression of inflammation-related proteins (IL-1ß: 69.7% ± 18.1% vs 20.2% ± 4.9%, respectively; MMP-13: 79.6% ± 12.6% vs 25.3% ± 9.5%; ADAMTS-4: 83.9% ± 12.2% vs 24.3% ± 11.1%; NITEGE: 89.7% ± 7.7% vs 39.8% ± 20.5%) (P < .001). Head-neck and acetabular cartilage in the early and late FAI groups showed a similar degree of degeneration. Moreover, a similar expression of inflammation-related proteins was observed between the early and late FAI groups for head-neck cartilage (IL-1ß: 69.7% ± 18.1% vs 72.5% ± 13.2%; MMP-13: 79.6% ± 12.6% vs 71.4% ± 18.8%; ADAMTS-4: 83.9% ± 12.2% vs 82.6% ± 12.5%; COL2: 93.6% ± 3.9% vs 92.5% ± 5.8%; NITEGE: 89.7% ± 7.7% vs 95.7% ± 4.7%) and acetabular cartilage (IL-1ß: 83.3% ± 24.8% vs 80.7% ± 15.6%; MMP-13: 94.3% ± 9.7% vs 85.2% ± 12.3%; ADAMTS-4: 98.5% ± 2.3% vs 98.4% ± 3.4%; COL2: 99.8% ± 0.7% vs 99.7% ± 1.1%; NITEGE: 96.7% ± 6.7% vs 99.2% ± 2.2%). In contrast, synovitis was minimal with a low expression of IL-1ß in the early FAI group compared with the late FAI group. CONCLUSION: Hip cartilage exhibited an OA phenotype in patients with early-stage FAI, similar to what was observed in hip OA secondary to FAI. Severe synovitis was only evident with late-stage FAI. CLINICAL RELEVANCE: This study supports the concept that early hip impingement is associated with cartilage degeneration and catabolism.

Inflammatory Response of Articular Cartilage to Femoroacetabular Impingement in the Hip.

BACKGROUND: Femoroacetabular impingement (FAI) has been proposed as an etiologic factor in up to 50% of hips with osteoarthritis (OA). Inflammation is thought to be one of the main initiators of OA, yet little is known about the origin of intra-articular inflammation in FAI hips. HYPOTHESIS: Articular cartilage from the impingement zone of patients with FAI has high levels of inflammation, reflecting initial inflammatory process in the hip. STUDY DESIGN: Controlled laboratory study. METHODS: Head-neck cartilage samples were obtained from patients with cam FAI (cam FAI, early FAI; n = 15), advanced OA secondary to cam FAI (FAI OA, late FAI; n = 15), and advanced OA secondary to developmental dysplasia of the hip (DDH OA, no impingement; n = 15). Cartilage procured from young adult donors (n = 7) served as control. Safranin O-stained sections were assessed for cartilage abnormality. Tissue viability was detected by TUNEL assay. Immunostaining of interleukin 1ß (IL-1ß), catabolic markers (matrix metalloproteinase 13 [MMP-13], a disintegrin and metalloproteinase with thrombospondin motif 4 [ADAMTS-4], aggrecan antibody to C-terminal neoepitope [NITEGE]), and an anabolic marker (type II collagen [COL2]) was performed to evaluate molecular inflammation and metabolic activity. The average percentage of immunopositive cells from the total cell count was calculated. Kruskal-Wallis test followed by Steel-Dwass post hoc test was used for multiple comparisons. RESULTS: Microscopic osteoarthritic changes were more prevalent in cartilage of cam FAI and FAI OA groups compared with DDH OA and control groups. Cartilage in cam FAI and FAI OA groups, versus the DDH group, had higher expression of inflammatory molecules IL-1ß (69.7% ± 18.1% and 72.5% ± 13.2% vs 32.7% ± 14.4%, respectively), MMP-13 (79.6% ± 12.6% and 71.4% ± 18.8% vs 38. 5% ± 13.3%), ADAMTS-4 (83.9% ± 12.2% and 82.6% ± 12.5% vs 45.7% ± 15.5%), and COL2 (93.6% ± 3.9% and 92.5% ± 5.8% vs 53.3% ± 21.0%) (P < .001). Expression of NITEGE was similar among groups (cam FAI, 89.7% ± 7.7%; FAI OA, 95.7% ± 4.7%; DDH OA, 93.9% ± 5.2%; P = .0742). The control group had minimal expression of inflammatory markers. Inflammatory markers were expressed in all cartilage zones of early and late FAI but only in the superficial zone of the no impingement group. CONCLUSION: Cartilage from the impingement zone in FAI is associated with a high expression of inflammatory markers, extending throughout all cartilage zones. CLINICAL RELEVANCE: Inflammation associated with FAI likely has a deleterious effect on joint homeostasis. Further clinical and translational studies are warranted to assess whether and how surgical treatment of FAI reduces molecular inflammation.

Inhibition of the Prostaglandin EP-1 Receptor in Periosteum Progenitor Cells Enhances Osteoblast Differentiation and Fracture Repair.

Fracture healing is a complex and integrated process that involves mesenchymal progenitor cell (MPC) recruitment, proliferation and differentiation that eventually results in bone regeneration. Prostaglandin E2 (PGE2) is an important regulator of bone metabolism and has an anabolic effect on fracture healing. Prior work from our laboratory showed EP1-/- mice have enhanced fracture healing, stronger cortical bones, higher trabecular bone volume and increased in vivo bone formation. We also showed that bone marrow MSCs from EP1-/- mice exhibit increased osteoblastic differentiation in vitro. In this study we investigate the changes in the periosteal derived MPCs (PDMPCs), which are crucial for fracture repair, upon EP1 deletion. EP1-/- PDMPCs exhibit increased numbers of total (CFU-F) and osteoblastic colonies (CFU-O) as well as enhanced osteoblastic and chondrogenic differentiation. Moreover, we tested the possible therapeutic application of a specific EP1 receptor antagonist to accelerate fracture repair. Our findings showed that EP1 antagonist administration to wild type mice in the early stages of repair similarly resulted in enhanced CFU-F, CFU-O, and osteoblast differentiation in PDMPCs and resulted in enhanced fracture callus formation at 10 days post fracture and increased bone volume and improved biomechanical healing of femur fractures at 21 days post fracture.

Peripheral Blood Stem Cell Therapy Does Not Improve Outcomes of Femoral Head Osteonecrosis With Cap-Shaped Separated Cartilage Defect.

A combination treatment with porous tantalum rod implantation and intra-arterial infusion of peripheral blood stem cells (PBSCs) provides a promise for treating early and intermediate stages of osteonecrosis of the femoral head (ONFH). However, its clinical indications and application restrictions remain unclear. This study aims to determine the clinical, histological, and radiological outcomes of a combination treatment using mechanical support and a targeted intra-arterial infusion of PBSCs for painful ONFH with a cap-shaped separation (CSS) cartilage defect. Compared with the standard pain management (control group), this combination treatment did not improve the Harris Hip Score (HHS) at 36 months. Micro-CT and histologic analyses showed severe focal destruction in all CSS-ONFH femoral heads in both the combination and control groups. Femoral heads showed a higher percentage of bone lesions in the combination treatment group than in the control group. There was no significant difference in osteoclast number in the subchondral bone areas between the two groups. A high level of expression of inflammatory cytokines, including tumor necrosis factor-α and interleukin-1ß, was detected in blood vessels around the subchondral bone in both groups. The RANKL/OPG (receptor activator of the nuclear factor-kB ligand/osteoprotegerin) ratio was also similar between the control and combination treatment groups. Our results indicate that this combination treatment is not an effective method for the treatment of patients with painful CSS-ONFH. Moreover, this combination treatment did not inhibit inflammatory osteoclastogenesis in patients with more advanced disease. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:269-276, 2020.

Patient-Reported Outcomes Measurement Information System physical function correlates with Toronto Extremity Salvage Score in an orthopaedic oncology population.

BACKGROUND: The National Institute of Health's Patient-Reported Outcomes Measurement Information System (PROMIS) uses computerised-adaptive testing to reduce survey burden and improve sensitivity. PROMIS is being used across medical and surgical disciplines but has not been studied in orthopaedic oncology. QUESTIONS/PURPOSES: The aim of the study was to compare PROMIS measures with upper extremity (UE) and lower extremity (LE) Toronto Extremity Salvage Score (TESS) by assessing the following: (1) responder burden, (2) correlation between scores and (3) floor/ceiling effects. PATIENTS AND METHODS: This cross-sectional trial analysed all 97 adult patients treated surgically for a bone or soft tissue tumour at a tertiary institution between November 2015 and March 2016. TESS (UE or LE) and PROMIS (Physical Function, Pain Interference and Depression) surveys were administered preoperatively. Pearson correlations between each PROMIS domain and TESS were calculated, as were floor/ceiling effects of each outcome measure. RESULTS: (1) Completion of three PROMIS questionnaires required a mean total of 16.8 (+/- 5.8 standard deviation) questions, compared with 31 and 32 questions for the LE and UE TESS questionnaires, respectively. (2) The PROMIS Physical Function scores demonstrated a strong positive correlation with the LE TESS (r = 0.84; 95% confidence interval [CI], 0.72-0.91; p < 0.001) and moderate positive correlation with the UE TESS (r = 0.64; 95% CI, 0.34-0.83; p = 0.055). The PROMIS Depression scores demonstrated a weak negative correlation with both the LE TESS (r = -0.38; 95% CI, -0.61 to -0.10; p = 0.010) and with UE TESS (r = -0.38; 95% CI, -0.67 to -0.01; p = 0.055). The PROMIS Pain Interference scores demonstrated a strong negative correlation with the LE TESS (r = -0.71; 95% CI, -0.83 to -0.52; p < 0.001) and a moderate negative correlation with the UE TESS (r = -0.62; 95% CI, -0.81 to -0.30; p = 0.001). (3) The UE TESS had a range of scores from 16 to 100 with a 27% ceiling effect and no floor effect, and the LE TESS had a range from 10 to 98 with no floor or ceiling effect. There was no floor or ceiling effect for any PROMIS measures. CONCLUSIONS: In an orthopaedic oncology population, the PROMIS Physical Function and Pain Interference scores correlate with the TESS and have the benefit of reduced survey burden and ceiling effect. The PROMIS Depression scores may provide additional information regarding patient outcomes not captured by the TESS. LEVEL OF EVIDENCE: Level III. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: Patient reported outcome measures asses patients' symptoms, function and health-related quality of life and are designed to capture more clinical information than can be gathered by objective medial testing alone. As reimbursements and the understanding of patient outcomes are becoming tied to performance on PROMIS measures, it is an important step to establish how PROMIS measures correlate and compare to traditional legacy measures.

Variation in the Delivery of Inpatient Orthopaedic Care to Medicaid Beneficiaries within a Single Metropolitan Region.

BACKGROUND: There is variability in access to and utilization of orthopaedic care, particularly for those with Medicaid insurance. One potential contributor is perceived unwillingness of surgeons and hospitals to accept underinsured patients. We used administrative data to examine the payer mix for select inpatient orthopaedic surgical procedures at all hospitals within a single region, hypothesizing that the delivery of orthopaedic surgery to Medicaid beneficiaries varies highly at the hospital level. METHODS: Using administrative data, we analyzed inpatient hospitalizations for elective cases (total knee or hip arthroplasty; spinal decompression or fusion) and trauma cases (hip hemiarthroplasty; femoral or tibial and fibular fracture repair) among 22 hospitals in a single region from 2011 to 2016 for patients who were 18 to 64 years of age. The primary outcome was the percentage of each hospital's caseload with Medicaid listed as the primary payer. The secondary outcome measured each hospital's Medicaid percentage against the percentage of Medicaid-insured individuals within 10 miles of the hospital (Medicaid share ratio), using a ratio of 1 as a benchmark. To quantify variation, we calculated a weighted coefficient of variation of the Medicaid share ratio for all cases combined, elective cases only, and trauma cases only. RESULTS: For all cases (n = 19,204), the mean percentage of Medicaid-funded surgical procedures was 7.6% (range, 0.2% to 57.3%). The mean Medicaid share ratio was 1.0 (range, 0.05 to 4.20). Across 22 hospitals, the weighted coefficient of variation for Medicaid share was 69, indicating very high variation. For elective cases alone, the mean percentage of Medicaid-funded surgical procedures was 5.5% (range, 0.2% to 64.6%). The mean Medicaid share ratio was 0.71 (range, 0.05 to 4.73), and the weighted coefficient of variation was 93. For trauma cases alone, Medicaid-funded surgical procedures were 14.7% (range, 0.0% to 35.7%). The mean Medicaid share ratio was 2.0 (range, 0 to 3.93), and the weighted coefficient of variation was 34. CONCLUSIONS: Delivery of care was highly variable when benchmarking against the insurance composition of each hospital's surrounding community. Although generalizability to other regions is limited, our findings support previously asserted notions that delivery of orthopaedic care may differ on the basis of socioeconomic markers (such as insurance status). If not addressed, these inequities may exacerbate existing racially and socioeconomically based disparities in care.

Treatment of intra-articular hip malignancy with extra-articular resection, preservation of the acetabular columns, and total hip arthroplasty.

Intra-articular malignant lesions of the hip present significant challenges. Resection often requires large resection of the acetabular bone and pelvic columns. Concurrent reconstruction options after intra-articular hip tumors are challenging and may necessitate the use of techniques and implants with uncertain long-term survivorship. We present a case of an intra-articular hip malignancy with extra-articular resection and preservation of the acetabular columns with reconstruction using a cementless acetabular shell fixed with screws.

Safety of Overlapping Inpatient Orthopaedic Surgery: A Multicenter Study.

BACKGROUND: Although overlapping surgery is used to maximize efficiency, more empirical data are needed to guide patient safety. We conducted a retrospective cohort study to evaluate the safety of overlapping inpatient orthopaedic surgery, as judged by the occurrence of perioperative complications. METHODS: All inpatient orthopaedic surgical procedures performed at 5 academic institutions from January 1, 2015, to December 31, 2015, were included. Overlapping surgery was defined as 2 skin incisions open simultaneously for 1 surgeon. In comparing patients who underwent overlapping surgery with those who underwent non-overlapping surgery, the primary outcome was the occurrence of a perioperative complication within 30 days of the surgical procedure, and secondary outcomes included all-cause 30-day readmission, length of stay, and mortality. To determine if there was an association between overlapping surgery and a perioperative complication, we tested for non-inferiority of overlapping surgery, assuming a null hypothesis of an increased risk of 50%. We used an inverse probability of treatment weighted regression model adjusted for institution, procedure type, demographic characteristics (age, sex, race, comorbidities), admission type, admission severity of illness, and clustering by surgeon. RESULTS: Among 14,135 cases, the frequency of overlapping surgery was 40%. The frequencies of perioperative complications were 1% in the overlapping surgery group and 2% in the non-overlapping surgery group. The overlapping surgery group was non-inferior to the non-overlapping surgery group (odds ratio [OR], 0.61 [90% confidence interval (CI), 0.45 to 0.83]; p < 0.001), with reduced odds of perioperative complications (OR, 0.61 [95% CI, 0.43 to 0.88]; p = 0.009). For secondary outcomes, there was a significantly lower chance of all-cause 30-day readmission in the overlapping surgery group (OR, 0.67 [95% CI, 0.52 to 0.87]; p = 0.003) and shorter length of stay (e, 0.94 [95% CI, 0.89 to 0.99]; p = 0.012). There was no difference in mortality. CONCLUSIONS: Our results suggest that overlapping inpatient orthopaedic surgery does not introduce additional perioperative risk for the complications that we evaluated. The suitability of this practice should be determined by individual surgeons on a case-by-case basis with appropriate informed consent. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Scholarly Success of Orthopaedic Surgeons Participating in the Clinician Scholar Career Development Program.

BACKGROUND: A concern exists about the decline in young orthopaedic surgeons pursuing careers as clinician-researchers. One program designed to address this concern is the American Academy of Orthopaedic Surgeons/Orthopaedic Research and Education Foundation/Orthopaedic Research Society (AAOS/OREF/ORS) Clinician Scholar Career Development Program (CSCDP). The aims of this study were to better understand the characteristics of CSCDP participants and how the experience effects involvement in career-impacting opportunities and scholarly activity. METHODS: This study was a retrospective analysis. CSCDP participants from 2003 to 2014 were recorded, and demographic information was collected. An Internet search was utilized to determine each surgeon's current practice environment. The National Institutes of Health (NIH) Research Portfolio Online Reporting Tools Expenditures and Results (RePORTER) database was used to track NIH funding. The OREF and its web site were used to query OREF grant funding. American Orthopaedic Association (AOA) Traveling Fellowship awardees were recorded from the AOA web site. Specialty-specific traveling fellowship awardee information was collected via organization web sites, and direct-contact, scholarly activity, and impact were determined using the Scopus database Hirsch index (h-index). RESULTS: Two hundred and thirty-two individuals (229 confirmed current orthopaedic surgeons) participated in the CSCDP. Fifteen (6.6%), 41 (17.9%), 20 (8.7%), and 17 (7.4%) former CSCDP participants have been awarded NIH funding, OREF grant support, AOA Traveling Fellowships, and/or specialty-specific traveling fellowships, respectively. Those involved in any of the career-impactful opportunities post-CSCDP have had higher scholarly activity and impact compared with those who were not involved in the career-impactful opportunities (h-index: 15.9 [standard deviation (SD), 8.1] versus 10.0 [SD, 5.7], p < 0.0001). No scholarly activity and impact differences existed between orthopaedic subspecialties (p = 0.077). CONCLUSIONS: The CSCDP appears to play an important role in promoting clinician-researcher careers in orthopaedic surgery. CLINICAL RELEVANCE: The CSCDP must continue to adapt to the surrounding health-care landscape to achieve an even better success rate in creating clinician-researchers who will further advance musculoskeletal health and discovery for the betterment of the patients and the profession.

Distinct metabolic programs induced by TGF-ß1 and BMP2 in human articular chondrocytes with osteoarthritis.

OBJECTIVES: Cellular energy metabolism is important for the function of all tissues, including cartilage. Recent studies indicate that superficial and deep subpopulations of articular chondrocytes (ACs) have distinct metabolic profiles. At the cellular and molecular level, osteoarthritis (OA) is characterised by alteration from a healthy homoeostatic state towards a catabolic state. Several molecular pathways, including transforming growth factor beta (TGF-ß) and bone morphogenetic protein (BMP) signalling, have been identified as critical players in the pathogenesis and progression of OA. However, the manner in which these factors influence cellular energy metabolism in ACs is not well understood. This study investigates the effect of TGF-ß or BMP signalling on energy metabolism in human articular chondrocytes (hACs). METHODS: ACs were isolated from residual macroscopically full thickness and intact cartilage from the femoral condyle of human samples obtained from patients with OA. ACs were treated with Vehicle (control), TGF-ß1 or BMP2 for 48-72 hours. Metabolic assays were performed to determine glucose consumption, lactate production and adenosine triphosphate (ATP) production, whereas the mitochondrial stress test was performed to determine oxygen consumption rate. Protein was isolated to assess translational activity and was evaluated using Western blot. RESULTS: We showed that TGF-ß1, known to maintain chondrocyte homoeostasis, stimulated glycolysis by upregulating key glycolytic factors, such as glucose transporter 1 (Glut1) and hexokinase II, while reducing oxidative phosphorylation in hACs. In contrast, BMP2 enhanced mitochondrial metabolism and oxidative phosphorylation and had a minimal effect on key glycolytic regulators. CONCLUSIONS: Our data revealed distinct metabolic programs induced by TGF-ß1 and BMP2 in hACs, suggesting that the regulation of cellular metabolism may represent a new mechanism underlying the pathogenesis of OA. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: The findings define the regulation of energy metabolism as a potential novel therapeutic approach for the treatment of OA.

PGE2 Receptor Subtype 1 (EP1) Regulates Mesenchymal Stromal Cell Osteogenic Differentiation by Modulating Cellular Energy Metabolism.

Mesenchymal stromal cells (MSCs) are multipotent progenitors capable of differentiation into osteoblasts and can potentially serve as a source for cell-based therapies for bone repair. Many factors have been shown to regulate MSC differentiation into the osteogenic lineage such as the Cyclooxygenase-2 (COX2)/Prostaglandin E2 (PGE2) signaling pathway that is critical for bone repair. PGE2 binds four different receptors EP1-4. While most studies focus on the role PGE2 receptors EP2 and EP4 in MSC differentiation, our study focuses on the less studied, receptor subtype 1 (EP1) in MSC function. Recent work from our laboratory showed that EP1-/- mice have enhanced fracture healing, stronger cortical bones, higher trabecular bone volume and increased in vivo bone formation, suggesting that EP1 is a negative regulator of bone formation. In this study, the regulation of MSC osteogenic differentiation by EP1 receptor was investigated using EP1 genetic deletion in EP1-/- mice. The data suggest that EP1 receptor functions to maintain MSCs in an undifferentiated state. Loss of the EP1 receptor changes MSC characteristics and permits stem cells to undergo more rapid osteogenic differentiation. Notably, our studies suggest that EP1 receptor regulates MSC differentiation by modulating MSC bioenergetics, preventing the shift to mitochondrial oxidative phosphorylation by maintaining high Hif1α activity. Loss of EP1 results in inactivation of Hif1α, increased oxygen consumption rate and thus increased osteoblast differentiation. J. Cell. Biochem. 118: 4383-4393, 2017. © 2017 Wiley Periodicals, Inc.