Orthopedic Student Scholar Presentation Awardees

2019-2020

Joshua T. Bram (Awardee), Julien T. Aoyama, R. Justin Mistovich, Yi-Meng Yen, Henry B. Ellis, Jr., R. Jay Lee, Peter D. Fabricant, Daniel W. Green, Aristides I. Cruz, Jr., Scott McKay, Gregory A. Schmale, Theodore J. Ganley

AAOS Poster Presentation

Risk factors for Arthrofibrosis in Tibial Spine Fractures: a National 10-site Multicenter Study

Introduction: Tibial spine fractures are common pediatric injuries with similar mechanism of injury to anterior cruciate ligament tears. Post-operative arthrofibrosis remains the most common complication following treatment of this injury, and many patients require subsequent manipulation under anesthesia. Several prior studies have examined risk factors for the development of arthrofibrosis, but with small patient populations and varying reported predictors. Therefore, our objective was to identify risk factors for arthrofibrosis in the largest known cohort of pediatric tibial spine patients.

Methods:This was a retrospective, multi-center study across ten institutions of 448 patients <25 years old who presented to care with a tibial spine fracture between 1/2000 and 2/2019. Patient records were reviewed for a multitude of pre-operative, intra-operative, and post-operative characteristics. Patients were then separated into two cohorts based on if they suffered from post-treatment arthrofibrosis.

Results: Chart review demonstrated that 43 (9.6%) of the patients suffered from post-treatment arthrofibrosis. There were no demographic differences observed between the two groups. However, based on MRIs at the time of injury, distal femoral and proximal tibial growth plates were more frequently closed in the arthrofibrosis group (17.6% vs 4.4%, p=0.023 for both comparisons). Additionally, there was no difference in Meyers & McKeever (MM) classification (p=0.597). All arthrofibrosis patients received operative treatment (p=0.003), though there was no difference in fixation technique (p=0.734). Intraoperatively, a higher number of screws were used in the arthrofibrosis group (p=0.002) with the placement of hardware more likely to be epiphyseal (p=0.007). Other operative parameters including number of sutures were not different. Post-operatively, arthrofibrosis patients were more likely to have been immobilized in a cast (p<0.001) with no difference observed for weight-bearing status. After multivariate regression, screw number (OR 8.9, CI 1.9-41.7, p=0.005) and immobilization in a cast (OR 7.8, CI 1.0-60.4, p=0.049) remained significant predictors of post-treatment arthrofibrosis.

Conclusion: This serves as the largest study of tibial spine fractures to analyze risk factors for the development of post-treatment arthrofibrosis. Our study demonstrates that pre-operative factors were largely similar between groups, but that intra- operative decisions, including the number of screws used for fixation and placement of hardware in relation to the physis, were significant predictors of post-treatment arthrofibrosis. These findings may influence operative decision-making in tibial spine fracture patients. Additionally, post-operative immobilization in a cast should be avoided given the high risk of arthrofibrosis.

Kevin Pirruccio (Awardee), Ajay Premkumar, and Neil P. Sheth

AAOS Podium Presentation

The Burden of Prosthetic Hip Dislocations in the U.S. is Projected to Significantly Increase by 2035

Introduction: Prosthetic hip dislocation is a common, costly complication of THA. Despite this, the national burden of prosthetic hip dislocations remains uncharacterized in the United States, especially pertaining to injuries occurring years after the index procedure. This study examines historical and projected national estimates of prosthetic hip dislocations presenting to U.S. emergency departments between 2000 and 2035.

Methods: We conducted a cross-sectional, retrospective epidemiological study using narratives in the National Electronic Injury Surveillance System (NEISS) database (2000-2018) to identify an estimated 72,760 prosthetic hip implant dislocations presenting to U.S. emergency departments. Estimates for the prevalence of individuals living with a total hip implant were derived from the literature.

Results: The national estimate of prosthetic hip dislocations presenting to U.S. emergency departments rose significantly (p < 0.001) between 2000 (N=2,395; 95% C.I. 1,264 - 3,526) and 2018 (N=8,089; 95% C.I. 3,825 - 12,353). These increases are likely driven by increased numbers of people living with THA overall, since between 2000 and 2018, the average incidence of prosthetic hip dislocation (0.15%; C.I. 0.08% - 0.22%) in patients living with hip implants has not changed significantly. Linear regression modeling (R2 = 0.70, p < 0.01) projected an increasing number of dislocations through 2035, predicting 11,390 national cases per year by this date.

Conclusion: Driven by increases in THA, the annual volume of prosthetic hip dislocations presenting to U.S. emergency departments has increased significantly since 2000, and is projected to continue to rise sharply. Future advances in surgical technique, prosthesis design, and injury prevention policies aimed at decreasing the rate of THA dislocation would help alleviate this mounting national health burden.

Jordan Stanley Cohen, Alex Gu, Chapman Wei, Nicolas A. Selemon (Awardee), Jiabin Liu, Peter Keyes Sculco

AAOS Poster Presentation

Preoperative Estimated Glomerular Filtration Rate Is a Marker for Postoperative Complications Following Revision Total Hip Arthroplasty

Introduction: Patients undergoing revision arthroplasty suffer high rates of complications and readmission. It is useful to identify patients at elevated risk for adverse events. In primary THA patients, chronic kidney disease (CKD) has been associated with readmission risk but not mortality, DVT, PE, or infection. However, the current literature has not shown whether these findings are applicable to revision THA patients. This study quantifies the impact of impaired renal filtration on complications after revision THA.

Methods: A retrospective cohort study was conducted using the ACS NSQIP database. Patients who underwent revision THA between 2007 and 2014 were identified and the estimated glomerular filtration rate (eGFR) was calculated for each patient. The incidence and predictors of adverse events following surgery were evaluated with univariate and multivariate analyses where appropriate.

Results: In the 8,898 revision THA procedures analyzed, 2,527 patients suffered at least one complication. The most frequent complications were transfusion (2,123), wound complications (332), UTI (116), sepsis (103), and pulmonary complications (87). In the univariate analysis, decreased eGFR was associated with likelihood of suffering any complication, pulmonary complications, cardiac complications, renal complications, transfusion, mortality, and extended length of stay. In the multivariate analysis, patients with normal renal function were less likely than patients with eGFR<30 ml/min/1.73 m2 to experience any complication (OR 0.69; 95% C.I. 0.48-0.99), cardiac complications (OR 0.30; 95% C.I. 0.09-0.96), transfusion (O.R. 0.62; 95% C.I. 0.42-0.89), and extended length of stay (O.R. 0.42; 95% C.I. 0.27-0.65). DISCUSSION AND

Conclusion: 28% of patients who undergo revision THA will experience a complication. Complications are more frequent in patients with diminished filtration, partially due to their poor health status. Multivariate analysis showed eGFR<30 ml/min/1.73 m2 independently predicts risk for overall complications, cardiac complications, transfusion, and extended length of stay after revision THA.