Department of Orthopaedic Surgery Works

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Endogenous versus Exogenous Growth Factor Regulation of Articular Chondrocytes
(Wiley, 2014) Shi, Shuiliang; Chan, Albert G.; Mercer, Scott; Eckert, George J.; Trippel, Stephen B.; Orthopaedic Surgery, School of Medicine
Seasonal variation in children with developmental dysplasia of the hip
(Sage, 2014) Loder, Randall T.; Shafer, Cody; Orthopaedic Surgery, School of Medicine
Background: It has been postulated that developmental dysplasia of the hip (DDH) is more frequent in infants born in the winter months. It was the purpose of this study to ascertain if there was any seasonal variation in DDH at the author's institution and compare/contrast our results with those in the literature using rigorous mathematical fitting. Methods: All children with DDH treated at the author's institution from 1993 to 2012 were identified. The month of birth was recorded and temporal variation was analyzed using cosinor analysis. Similar data from the literature was analyzed. Results: There were 424 children (363 girls, 61 boys). An additional 22,936 children were added from the literature for a total of 23,360. Pearson's Chi-square test demonstrated a non-uniform distribution in the month of birth for both our 424 children as well as the combined literature series in both the Northern and Southern hemispheres. Cosinor analysis of the 424 children demonstrated double peaks in mid-March and mid-October. For the entire 23,360 children, no seasonal variation was observed in 2,205 (9.4 %), a single winter peak in 16,425 (70.3 %), a single summer peak in 1,280 (5.5 %), and double peaks in the spring and autumn in 3,450 (14.8 %). Conclusions: This study partly supports the hypothesis of tight clothing/cold temperature as one factor in the etiology of DDH with the tighter clothing/swaddling increasing the risk of DDH. However ~20 % of the DDH births demonstrated a non-winter peak. The single summer and double spring/autumn peaks, as well as in those series where no seasonal variation was noted, refutes the cold winter clothing hypothesis. Perhaps these different patterns in seasonal variation represent the heterogeneity of the genetic factors in DDH interacting with external factors (temperature and clothing) and internal factors (metabolic). Further study will be required to understand these different patterns in DDH seasonal variation.
Letter to the Editor: Equity360: Gender, Race, and Ethnicity: Sex and Fairness in Sports
(Wolters Kluwer, 2024) Loder, Randall T.; Orthopaedic Surgery, School of Medicine
Proteomic Analyses of Plasma from Patients with Fracture Related Infection Reveals Systemic Activation of the Complement and Coagulation Cascades
(Wolters Kluwer, 2024) Becker, Kevin; Sharma, Ishani; Slaven, James E.; Mosley, Amber L.; Doud, Emma H.; Malek, Sarah; Natoli, Roman M.; Orthopaedic Surgery, School of Medicine
Objectives: The objective of this study was to compare plasma proteomes of patients with confirmed fracture-related infections (FRIs) matched to noninfected controls using liquid chromatography-mass spectrometry. Design: This was a prospective case-control study. Setting: The study was conducted at a single, academic, Level 1 trauma center. Patient selection criteria: Patients meeting confirmatory FRI criteria were matched to controls without infection based on fracture region, age, and time after surgery from June 2019 to January 2022. Tandem mass tag liquid chromatography-mass spectrometry analysis of patient plasma samples was performed. Outcome measures and comparisons: Protein abundance ratios in plasma for patients with FRI compared with those for matched controls without infection were calculated. Results: Twenty-seven patients meeting confirmatory FRI criteria were matched to 27 controls. Abundance ratios for more than 1000 proteins were measured in the 54 plasma samples. Seventy-three proteins were found to be increased or decreased in patients with FRI compared with those in matched controls (unadjusted t test P < 0.05). Thirty-two of these proteins were found in all 54 patient samples and underwent subsequent principal component analysis to reduce the dimensionality of the large proteomics dataset. A 3-component principal component analysis accounted for 45.7% of the variation in the dataset and had 88.9% specificity for the diagnosis of FRI. STRING protein-protein interaction network analysis of these 3 PCs revealed activation of the complement and coagulation cascades through the Reactome pathway database (false discovery rates <0.05). Conclusions: Proteomic analyses of plasma from patients with FRI demonstrate systemic activation of the complement and coagulation cascades. Further investigation along these lines may help to better understand the systemic response to FRI and improve diagnostic strategies using proteomics.
Results of Anatomic Total Shoulder Arthroplasty with the Arthrex Eclipse Stemless Humeral Implant in Patients Over 70 Years of Age
(Elsevier, 2025) Dillon, Mark T.; Denard, Patrick J.; ShARC Group; Werner, Brian C.; Orthopaedic Surgery, School of Medicine
Background Anatomic total shoulder arthroplasty (aTSA) is a well-described technique for addressing glenohumeral osteoarthritis. Little has been written on outcomes for newer stemless humeral implants in older patients, with none looking specifically at an implant relying on screw fixation. The purpose of this study is to evaluate the clinical and radiographic outcomes for patients over 70 years of age undergoing aTSA with the Eclipse (Arthrex Inc., Naples, FL, USA) stemless humeral component. Methods A retrospective review using a multicenter shoulder arthroplasty registry was performed evaluating all patients over 70 years of age who underwent aTSA with a stemless humeral implant for a diagnosis of glenohumeral osteoarthritis and had a minimum follow-up of 2 years. Thirty-seven patients met the study criteria and were matched for comparative analysis to 37 patients 65 years and younger. Outcome scores were obtained preoperatively and at 2 years postoperatively using the visual analog scale, Constant-Murley, American Shoulder and Elbow Surgeons (ASES), and Western Ontario Osteoarthritis Index (WOOS) scores. The percentage of patients in each group who exceeded the Minimal Clinically Important Difference (MCID) for the ASES and WOOS was reported. When available, postoperative radiographs were evaluated for the presence of radiolucent lines and calcar resorption. Results There was a statistically significantly higher preoperative WOOS score in the older patient group; otherwise, there was no statistical difference between the 2 groups in regard to baseline scores or range of motion. At 2-year follow-up, older patients were noted to have significantly better visual analog scale, ASES, WOOS, and Constant-Murley scores than younger patients (P < .05). For the ASES, all patients over the age of 70 years achieved MCID compared with 84% of those 65 years and younger (P = .011), whereas for the WOOS, 100% of older patients achieved MCID compared with 86% of those in the control group (P = .022). Postoperative range of motion was generally not different between the 2 groups, although older patients had better active internal rotation at 90° of abduction (P = .002). Partial calcar resorption was noted in 1 patient in each age group. Radiolucent lines were noted in 2 patients over the age of 70 years and 1 patient 65 years or younger. Discussion Patients over the age of 70 years with glenohumeral osteoarthritis undergoing aTSA with a stemless humeral component have equivalent, if not better, outcomes when compared with younger patients. Age alone does not appear a limitation for stemless aTSA.
Patient- and Procedure-Specific Variables Associated With Removal or Revision of Radial Head Arthroplasty
(Kaiser Permanente, 2022) Dillon, Mark T.; Dontsi, Makdine; Alabaster, Amy; Vance, Michael C.; Orthopaedic Surgery, School of Medicine
Introduction: The purpose of this retrospective review was to identify risk factors associated with removal or revision following radial head arthroplasty. Methods: Patients undergoing primary radial head arthroplasty between 2009 and 2015 with a minimum follow-up of 1 year were identified. Descriptive and bivariate statistics were used to analyze the characteristics of patients requiring implant removal or revision and multivariable analysis was performed to calculate hazard ratios. Results: There were 312 patients included in the final cohort with a median follow-up of 3.8 years. Thirty-five patients (11.2%) underwent prosthesis removal or revision. There was an increased percentage of implants removed or revised in patients under age 40, with surgery performed for chronic indications compared to acute trauma, and with the use of press-fit stems compared to polished. Discussion: It appears younger patient age, chronic surgical indications, and certain aspects of prosthesis design may influence rates of removal or revision.
The effect of a statewide COVID-19 shelter-in-place order on shoulder arthroplasty for proximal humerus fracture volume and length of stay
(Elsevier, 2021) Dillon, Mark T.; Chan, Priscilla H.; Prentice, Heather A.; Royse, Kathryn E.; Paxton, Elizabeth W.; Okike, Kanu; Khatod, Monti; Navarro, Ronald A.; Orthopaedic Surgery, School of Medicine
Background: Although the COVID-19 pandemic has disrupted elective shoulder arthroplasty throughput, traumatic shoulder arthroplasty procedures are less apt to be postponed. We sought to evaluate shoulder arthroplasty utilization for fracture during the COVID-19 pandemic and California's associated shelter-in-place order compared to historical controls. Methods: We conducted a cohort study with historical controls, identifying patients who underwent shoulder arthroplasty for proximal humerus fracture in California using our integrated electronic health record. The time period of interest was following the implementation of the statewide shelter-in-place order: March 19, 2020-May 31, 2020. This was compared to three historical periods: January 1, 2020-March 18, 2020, March 18, 2019-May 31, 2019, and January 1, 2019-March 18, 2019. Procedure volume, patient characteristics, in-hospital length of stay, and 30-day events (emergency department visit, readmission, infection, pneumonia, and death) were reported. Changes over time were analyzed using linear regression adjusted for usual seasonal and yearly changes and age, sex, comorbidities, and postadmission factors. Results: Surgical volume dropped from an average of 4.4, 5.2, and 2.6 surgeries per week in the historical time periods, respectively, to 2.4 surgeries per week after shelter-in-place. While no more than 30% of all shoulder arthroplasty procedures performed during any given week were for fracture during the historical time periods, arthroplasties performed for fracture was the overwhelming primary indication immediately after the shelter-in-place order. More patients were discharged the day of surgery (+33.2%, P = .019) after the shelter-in-place order, but we did not observe a change in any of the corresponding 30-day events. Conclusions: The volume of shoulder arthroplasty for fracture dropped during the time of COVID-19. The reduction in volume could be due to less shoulder trauma due to shelter-in-place or a change in the indications for arthroplasty given the perceived higher risks associated with intubation and surgical care. We noted more patients undergoing shoulder arthroplasty for fracture were safely discharged on the day of surgery, suggesting this may be a safe practice that can be adopted moving forward.
The Epidemiology and Demographics of Slipped Capital Femoral Epiphysis
(Wiley, 2011-09-21) Loder, Randall T.; Skopelja, Elaine N.; Orthopaedic Surgery, School of Medicine
The etiology of slipped capital femoral epiphysis (SCFE) is unknown with many insights coming from epidemiologic/demographic information. A systematic medical literature review regarding SCFE was performed. The incidence is 0.33/100,000 to 24.58/100,000 children 8 to 15 years of age. The relative racial frequency, relative to Caucasians at 1.0, is 5.6 for Polynesians, 3.9 for Blacks, and 2.5 for Hispanics. The average age is 12.0 years for boys and 11.2 years for girls. The physiologic age when SCFE occurs is less variable than the chronologic age. The average symptom duration is 4 to 5 months. Most children are obese: >50% are >95th percentile weight for age with average BMI is 25-30 kg/m(2). The onset of SCFE is in the summer when north of 40°N. Bilaterality ranges from 18 to 50%. In children with bilateral involvement, 50-60% present with simultaneous SCFEs and those who present with a unilateral SCFE and subsequently develop a contralateral SCFE do so within 18 months. The age at presentation is younger for those who present with a unilateral SCFE and later develop a contralateral SCFE. The age-weight, age-height, and height test are useful to differentiate between an idiopathic and atypical SCFE.
The Epidemiology and Demographics of Legg-Calvé-Perthes' Disease
(Wiley, 2011-09-05) Loder, Randall T.; Skopelja, Elaine N.; Orthopaedic Surgery, School of Medicine
The etiology of Legg-Calvé-Perthes' disease (LCPD) is unknown. There are many insights however from epidemiologic/demographic information. A systematic medical literature review regarding LCPD was performed. The incidence ranges from 0.4/100,000 to 29.0/100,000 children <15 years of age. There is significant variability in incidence within racial groups and is frequently higher in lower socioeconomic classes. The typical age at presentation ranges from 4 to 8 years (average 6.5 years), except for children from the Indian subcontinent (average 9.5 years). There is a mild familial component. The children demonstrate impaired growth in height, skeletal age, and birth weight. This impaired growth coincides with an age appropriate reduced somatomedin A activity and decreased levels of IGF. LCPD can be associated with abnormalities in the coagulation cascade, including an increase in factor V Leiden mutation, low levels of protein C and/or S, and decreased antithrombin activity. There is decreased turnover in type I collagen and synthesis of type III collagen, as well as reduced levels of urinary glycosaminoglycans in the active phases of the disorder. Subtle abnormalities in the opposite hip and other minor/major congenital defects are reported. Children with LCPD are active and score abnormally in certain standardized psychological tests.
The Epidemiology and Demographics of Hip Dysplasia
(Wiley, 2011-10-10) Loder, Randall T.; Skopelja, Elaine N.; Orthopaedic Surgery, School of Medicine
The etiology of developmental dysplasia of the hip (DDH) is unknown. There are many insights, however, from epidemiologic/demographic information. A systematic medical literature review regarding DDH was performed. There is a predominance of left-sided (64.0%) and unilateral disease (63.4%). The incidence per 1000 live births ranges from 0.06 in Africans in Africa to 76.1 in Native Americans. There is significant variability in incidence within each racial group by geographic location. The incidence of clinical neonatal hip instability at birth ranges from 0.4 in Africans to 61.7 in Polish Caucasians. Predictors of DDH are breech presentation, positive family history, and gender (female). Children born premature, with low birth weights, or to multifetal pregnancies are somewhat protected from DDH. Certain HLA A, B, and D types demonstrate an increase in DDH. Chromosome 17q21 is strongly associated with DDH. Ligamentous laxity and abnormalities in collagen metabolism, estrogen metabolism, and pregnancy-associated pelvic instability are well-described associations with DDH. Many studies demonstrate an increase of DDH in the winter, both in the northern and southern hemispheres. Swaddling is strongly associated with DDH. Amniocentesis, premature labor, and massive radiation exposure may increase the risk of DDH. Associated conditions are congenital muscular torticollis and congenital foot deformities. The opposite hip is frequently abnormal when using rigorous radiographic assessments. The role of acetabular dysplasia and adult hip osteoarthritis is complex. Archeological studies demonstrate that the epidemiology of DDH may be changing.

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