Increased dislocation rates following total hip arthroplasty in patients with ankylosing spondylitis.

BACKGROUND: Patients with ankylosing spondylitis (AS) experience abnormal spinopelvic motion due to chronic inflammation of the axial skeleton, predisposing them to impingement and dislocation. The purpose of this study was to evaluate total hip arthroplasty (THA) dislocation rates in AS patients and evaluate the effects of age and gender on dislocation risk. METHODS: Patients who underwent primary THA from 2005 to 2014 were identified using the PearlDiver database. AS patients were compared to age- and gender-matched controls without AS. Patients with a history of spine pathology or spine surgery were excluded. Univariate analyses were performed based on age and sex to evaluate dislocation rates at 90 days, 6 months, 1 year, and 5 years postoperatively. RESULTS: A total of 2792 THA patients (59.6% male) with AS were identified and compared to an age- and gender-matched control group of 5582 THA patients (59.5% male) without AS or known spine pathology. At final follow-up, there were 96 dislocations (3.4%) in the AS group and 138 (2.5%) dislocations in the control group (OR 1.40; 95% CI, 1.08-1.83; p = 0.0118). AS patients ⩾70 years old had higher dislocation rates at all time points (OR range, 1.75-2.09; p < 0.05) compared to controls. At 5-year follow-up, dislocation-free survivorship was 95.7% (95% CI, 94.5-96.9%) for AS patients ⩾70 years old compared to 97.3% (95% CI, 96.6-98.0%) for patients ⩾70 years old without AS. CONCLUSIONS: Older AS patients have higher dislocation rates following THA. This effect is likely related to decreased spinopelvic motion in the sagittal plane, predisposing patients to impinge and dislocate.

Utilization of technology-assisted total hip arthroplasty in the United States from 2005 to 2018.

BACKGROUND: Successful outcomes in total hip arthroplasty (THA) rely in part on accurate component positioning, which may be optimized through the use of computer navigation and robot-assistance. Therefore, we queried a large national database to characterize national trends in technology-assisted THA utilization, determine whether these technologies were associated with increased hospital charges, and identify demographic factors associated with technology-assisted THA. METHODS: Using the Nationwide Inpatient Sample database, patients that underwent conventional THA, computer-navigated THA, and robot-assisted THA from 2005 to 2018 were identified. Patient and hospital demographics, charge data, and payer characteristics were collected. Temporal trends in utilization were reported. Univariate analyses were performed to compare differences between groups with multiple logistic regression analysis to account for confounders. RESULTS: In total, 3,428,208 patients undergoing THA from 2005 to 2018 were identified, of which 63,136 (1.8%) used computer navigation and 32,660 (1.0%) used robot-assistance. National utilization of computer navigation in THA increased from 0.1% to 1.9% between 2005 and 2018, while utilization of robot-assisted THA increased from <0.1% to 2.1% from 2008 to 2018. On multivariate analysis, technology-assisted THA was most commonly performed in urban hospitals in the Northeastern United States. Median hospital charges were increased for technology-assisted THAs relative to conventional THAs ($66,089 ± $254 vs $55,418 ± $43). CONCLUSIONS: Computer navigation and robot-assistance in THA demonstrated a consistent increase in utilization during the period examined, representing 4.0% of THAs performed in 2018. Patient and hospital characteristics including risk of mortality, geographic region, and teaching status were associated with increased utilization. Utilization of computer navigation was associated with increased hospital charges.

Single-stage bilateral reverse total shoulder arthroplasty for bilateral posterior shoulder fracture-dislocation following seizure: A case report.

INTRODUCTION: Posterior shoulder dislocations comprise a small percentage of shoulder dislocations. Even more uncommon are posterior shoulder fracture-dislocations, which are commonly associated with trauma, seizures, and electrical shock. PRESENTATION OF CASE: We present the case of a 64-year-old right-hand dominant male who sustained bilateral shoulder posterior fracture-dislocations after a hypoglycemia-induced seizure. The patient was treated with bilateral reverse total shoulder arthroplasties in a single-stage. He recovered well and continues to have excellent function and range of motion at 4-year follow-up. DISCUSSION: Treatment options for proximal humerus fracture-dislocations include open reduction internal fixation (ORIF), hemiarthroplasty, and reverse total shoulder arthroplasty (RTSA). The indications for reverse total shoulder arthroplasty continue to expand. CONCLUSION: This is a rare case of bilateral posterior shoulder fracture-dislocations. In similar cases, simultaneous reverse total shoulder arthroplasties can be considered as a viable treatment option.

Recalcitrant methicillin-resistant Staphylococcus aureus infection of bone cells: Intracellular penetration and control strategies.

AIMS: To characterize the intracellular penetration of osteoblasts and osteoclasts by methicillin-resistant Staphylococcus aureus (MRSA) and the antibiotic and detergent susceptibility of MRSA in bone. METHODS: Time-lapse confocal microscopy was used to analyze the interaction of MRSA strain USA300 with primary murine osteoblasts and osteoclasts. The effects of early and delayed antibiotic treatments on intracellular and extracellular bacterial colony formation and cell death were quantified. We tested the effects of cefazolin, gentamicin, vancomycin, tetracycline, rifampicin, and ampicillin, as well as agents used in surgical preparation and irrigation. RESULTS: MRSA infiltrated bone-resident cells within 15 to 30 minutes. Penetration was most effectively prevented with early (i.e. 30 minutes) antibiotic administration. The combined administration of rifampicin with other antibiotics potentiated their protective effects against MRSA-induced cytotoxicity and most significantly reduced extracellular bacterial bioburden. Gentamicin-containing compounds were most effective in reducing intracellular MRSA bioburden. Of the surgical preparation agents evaluated, betadine reduced in vitro MRSA growth to the greatest extent. CONCLUSION: The standard of care for open fractures involves debridement and antibiotics within the first six hours of injury but does not account for the window in which bacteria penetrate cells. Antibiotics must be administered as early as possible after injury or prior to incision to prevent intracellular infestation. Rifampicin can potentiate the capacity of antibiotic regimens to reduce MRSA-induced cytotoxicity.Cite this article: Bone Joint Res. 2020;9(2):49-59.

Population-based Survivorship of Computer-navigated Versus Conventional Total Knee Arthroplasty.

BACKGROUND: The goal of computer navigation in total knee arthroplasty (TKA) is to improve the accuracy of alignment. However, the relationship between this technology and implant longevity has not been established. The purpose of this study was to analyze survivorship of computer-navigated TKAs compared with traditionally instrumented TKAs. METHODS: The PearlDiver Medicare database was used to identify patients who underwent a primary TKA using conventional instrumentation versus computer navigation between 2005 and 2014. Conventional and computer-navigated cohorts were matched by age, sex, year of procedure, comorbidities, and geographic region. Kaplan-Meier curves were generated to estimate survivorship with aseptic mechanical complications, periprosthetic joint infection, and all-cause revision as end points. RESULTS: During the study period, 75,709 patients who underwent a computer-navigated TKA were identified and matched to a cohort of 75,676 conventional TKA patients from a cohort of 1,607,803 conventional TKA patients. No difference existed in survival between conventional instrumentation (94.7%) and navigated TKAs (95.1%, P = 0.06) at 5 years. A modest decrease was found in revisions secondary to mechanical complications associated with navigation (96.1%) compared with conventional instrumentation (95.7%, P = 0.02) at 5 years. No differences in revision rates because of periprosthetic joint infection were observed (97.9% versus 97.9% event-free survival, P = 0.30). In a subgroup of Medicare patients younger than 65 years of age, use of computer navigation was associated with a decrease in all-cause revision (91.4% versus 89.6% event free survival, P = 0.01) and revision secondary to mechanical complications (89.6% versus 87.8% event-free survival, P = 0.01) at 5 years. DISCUSSION: Among Medicare patients, no notable difference existed in TKA survival associated with the use of computer navigation at the 5-year follow-up. Use of computer navigation was associated with a slight decrease in revisions secondary to mechanical failure. Although improved survivorship was associated with patients younger than 65 years of age who had a navigated TKA, generalizability of these findings is limited given the unique characteristics of this Medicare subpopulation.

Evaluating the Standardized Letter of Recommendation Form in Applicants to Orthopaedic Surgery Residency.

INTRODUCTION: A standardized letter of recommendation (SLOR) form for orthopaedic surgery residency programs has recently been adopted for use, but it has not been scientifically evaluated. The purpose of this study is to investigate the usefulness of the SLOR form in the selection process. METHODS: All SLOR forms submitted to our institution over a single application cycle were extracted and analyzed. The United States Medical Licensing Examination Step 1 scores, grades in clinical rotations, Alpha Omega Alpha status, and the number of publications were recorded for each applicant. Correlations were calculated with Spearman rho, and inter-rater reliability was evaluated by calculating intraclass correlation coefficients. RESULTS: One thousand one hundred thirty-seven SLOR forms were analyzed for 513 applicants. There was substantial rank inflation with the SLOR form; the majority (92%) of applicants were rated as either ranked to match or in the top one-third of their rank list. Objective applicant factors such as grades and Step 1 scores demonstrated a very weak to nonexistent correlation with the summative rank (rho 0.07 to 0.13, P ≤ 0.012). Poor inter-rater reliability was observed with the intraclass correlation coefficient ranging from 0.22 to 0.33 (P < 0.001). CONCLUSIONS: The usefulness of the SLOR form is limited by the very high ratings observed for all questions, and in particular, the final summative rank. Measures to reduce rank inflation must be implemented to improve the discriminant ability of the SLOR form, and if this cannot be accomplished, perhaps the form should be abandoned. LEVEL OF EVIDENCE: Level III Retrospective.

Effect of Mental Health Conditions on Complications, Revision Rates, and Readmission Rates Following Femoral Shaft, Tibial Shaft, and Pilon Fracture.

OBJECTIVES: To evaluate the effect of pre-existing mental health (MH) conditions on 90-day complication, 90-day readmission, and all-time revision surgical intervention rates following femoral, tibial, and pilon fractures. DESIGN: Data were collected using a commercially available database software for which Current Procedural Terminology codes were used to identify patients who underwent surgical treatment of tibial, femoral, or pilon fractures. These patients were then subdivided into those with and without pre-existing MH condition using International Classification of Disease, Ninth Edition codes. Ninety-day postoperative complications, revision surgery, and 90-day readmission rates were then compared between those with and without MH conditions. SETTING: National databases of 70 million combined patients from 2007 to 2015. PATIENTS/PARTICIPANTS: Humana and Medicare insured patients. INTERVENTION: Surgical treatment of tibial, femoral, and pilon fractures. MAIN OUTCOME MEASUREMENTS: Ninety-day readmission, 90-day complications, and all-time revision surgical intervention. RESULTS: The total number of patients for femoral, tibial, and pilon treatment, respectively, included 6207, 6253, and 5940 without MH conditions and 4879, 5247, and 2911 with MH conditions. Femoral, tibial, and pilon readmission rates, revision rates, and complication rates were significantly higher among patients with MH disorders in matched cohorts after controlling for medical comorbidities (P ≤ 0.05 for all). CONCLUSIONS: Comorbid MH conditions are associated with higher postoperative complication, readmission, and revision surgery rates for treated femoral, tibial, and pilon fractures. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Trends in computer navigation and robotic assistance for total knee arthroplasty in the United States: an analysis of patient and hospital factors.

BACKGROUND: Computer navigation and robotic assistance technologies are used to improve the accuracy of component positioning in total knee arthroplasty (TKA), with the goal of improving function and optimizing implant longevity. The purpose of this study was to analyze trends in the use of technology-assisted TKA, identify factors associated with the use of these technologies, and describe potential drivers of cost. METHODS: The Nationwide Inpatient Sample database was used to identify patients who underwent TKA using conventional instrumentation, computer navigation, and robot-assisted techniques between 2005 and 2014. Variables analyzed include patient demographics, hospital and payer types, and hospital charges. Descriptive statistics were used to describe trends. Univariate and multivariate analyses were performed to identify differences between conventional and technology-assisted groups. RESULTS: Our analysis identified 6,060,901 patients who underwent TKA from 2005 to 2014, of which 273,922 (4.5%) used computer navigation and 24,084 (0.4%) used robotic assistance. The proportion of technology-assisted TKAs steadily increased over the study period, from 1.2% in 2005 to 7.0% in 2014. Computer navigation increased in use from 1.2% in 2005 to 6.3% in 2014. Computer navigation was more likely to be used in the Western United States, whereas robot-assisted TKAs were more likely to be performed in the Northeast. Increased hospital charges were associated with the use of technology assistance ($53,740.1 vs $47,639.2). CONCLUSIONS: The use of computer navigation and robot-assisted TKA steadily increased over the study period, accounting for 7.0% of TKAs performed in the United States in 2014. Marked regional differences in the use of these technologies were identified. The use of these technologies was associated with increased hospital charges.

Injections Prior to Rotator Cuff Repair Are Associated With Increased Rotator Cuff Revision Rates.

PURPOSE: To determine whether shoulder injections prior to rotator cuff repair (RCR) are associated with deleterious surgical outcomes. METHODS: Two large national insurance databases were used to identify a total of 22,156 patients who received ipsilateral shoulder injections prior to RCR. They were age, sex, obesity, smoking status, and comorbidity matched to a control group of patients who underwent RCR without prior injections. The 2 groups were compared regarding RCR revision rates. RESULTS: Patients who received injections prior to RCR were more likely to undergo RCR revision than matched controls (odds ratio [OR], 1.52; 95% confidence interval [CI], 1.38-1.68; P < .0001). Patients who received injections closer to the time of index RCR were more likely to undergo revision (P < .0001). Patients who received a single injection prior to RCR had a higher likelihood of revision (OR, 1.25; 95% CI, 1.10-1.43; P = .001). Patients who received 2 or more injections prior to RCR had a greater than 2-fold odds of revision (combined OR, 2.12; 95% CI, 1.82-2.47; P < .0001) versus the control group. CONCLUSIONS: This study strongly suggests a correlation between preoperative shoulder injections and revision RCR. There is also a frequency dependence and time dependence to this finding, with more frequent injections and with administration of injections closer to the time of surgery both independently associated with higher revision RCR rates. Presently, on the basis of this retrospective database study, orthopaedic surgeons should exercise due caution regarding shoulder injections in patients whom they are considering to be surgical candidates for RCR. LEVEL OF EVIDENCE: Level III, therapeutic study.

Total Hip Arthroplasty Bearing Surface Trends in the United States From 2007 to 2014: The Rise of Ceramic on Polyethylene.

BACKGROUND: Wear of the bearing surface is a critical element in determining the longevity of a total hip arthroplasty (THA). Over the past decade, concerns related to modern metal-on-metal (MoM) bearings and corrosion at the femoral head-neck interface have influenced surgeon selection of bearing surfaces. The purpose of this study is to analyze trends in THA bearing surface selection from 2007 through 2014 using a large national database. METHODS: The Nationwide Inpatient Sample database was used to extract bearing surface data from patients who underwent a primary THA between 2007 and 2014. Patients were grouped by bearing surface type: metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), MoM, and ceramic-on-ceramic (CoC) bearings. Descriptive statistics were employed to describe trends. Univariate and multivariate analyses were performed to identify differences between bearing surface groups. RESULTS: During the study period, 2,460,640 THA discharges were identified, of which 1,059,825 (43.1%) had bearing surface data. A total of 496,713 (46.9%) MoP, 307,907 (29.1%) CoP, 210,381 (19.9%) MoM, and 44,823 (4.2%) CoC cases were identified. MoM utilization peaked in 2008 representing 40.1% of THAs implanted that year and steadily declined to 4.0% in 2014. From 2007 to 2014, the use of CoP bearing surfaces increased from 11.1% of cases in 2007 to 50.8% of cases in 2014. In 2014, CoP utilization surpassed MoP which represented 42.1% of bearing surfaces that year. CONCLUSION: During the study period, MoM bearing surfaces decreased precipitously, while CoP surpassed MoP as the most popular bearing surface used in a THA.