Glenoid component loosening associated with increased critical shoulder angle at midterm follow-up.

BACKGROUND: Glenoid component loosening is a common failure mode of total shoulder arthroplasty (TSA). A larger critical shoulder angle (CSA) may cause superior glenoid component loading and more rapid component loosening. The purpose of this study was to define the relationship between the CSA and glenoid component loosening in midterm follow-up after TSA. METHODS: We conducted a retrospective study of 61 primary TSAs for osteoarthritis with an average follow-up of 5.0 ± 2.2 years without surgical revision. Standard true anteroposterior radiographs postoperatively and at longest follow-up were graded in a blinded and repetitive nature for pegged glenoid radiolucent lines and measured for the CSA. An "at-risk" glenoid was defined as grade 3 or higher lucency. RESULTS: The average CSA was 32° ± 5°, median midterm lucency grade was 2 (range, 0-5), and median progression of lucency grade was 1 (range, -1 to 4). At midterm follow-up, 20% of TSAs were grade 3 or higher mean glenoid lucency, with an average CSA of 36°. There was a statistically significant correlation between CSA and both glenoid lucency grade (odds ratio, 1.20 per degree CSA) and progression of lucency grade (odds ratio, 1.24). An increase in CSA of 10° was associated with a 6.2-fold increased odds of having an at-risk glenoid. CONCLUSION: This study identifies the CSA as a risk factor for glenoid component loosening after TSA. Our findings suggest that the CSA may be a modifiable factor during surgery to improve glenoid component outcomes.

Risk factors associated with blood transfusion after shoulder arthroplasty.

BACKGROUND: Closed-suction drainage has been studied extensively in hip and knee arthroplasty literature. However, little is known about outcomes in patients treated with drainage after shoulder arthroplasty, particularly relative to transfusion requirements. METHODS: All primary total and reverse total shoulder arthroplasties (TSAs and RSAs) performed at a single institution during a 5-year period were retrospectively reviewed. Data collected included patient demographic information, estimated blood loss (EBL), drain output, length of drain use, changes in hemoglobin (Hgb) level postoperatively, transfusions, and complications. A multivariable regression analysis was performed to identify independent risk factors for transfusion. RESULTS: There were no differences in surgery duration, EBL, or complications between TSA and RSA patients (P > .05). Patients undergoing RSA were older (74.0 vs. 68.4 years; P < .001) and had lower preoperative and postoperative Hgb levels (P < .001) compared with TSA patients. Reverse arthroplasty was also associated with longer hospital stays (2.8 vs. 2.2 days; P < .001), longer drain durations (1.6 vs. 1.2 days; P < .001), increased total wound drainage (209 vs. 168 m; P = .006), and higher transfusion rates (11.7% vs. 3.1%; P = .002). Independent risk factors for transfusion included low preoperative Hgb levels in both TSA (P = .024) and RSA (P = .002) and higher EBL in TSA (P = .031). CONCLUSION: Low preoperative Hgb level is an independent risk factor for requiring blood transfusion after TSA and RSA. Increased wound drainage was not a risk factor for transfusion, and the 40-mL increase in wound drainage found in RSA is of questionable clinical significance.

Reliability of a field-based drop vertical jump screening test for ACL injury risk assessment.

OBJECTIVES: There is an epidemic of anterior cruciate ligament (ACL) injuries in youth athletes. Poor neuromuscular control is an easily modifiable risk factor for ACL injury, and can be screened for by observing dynamic knee valgus on landing in a drop vertical jump test. This study aims to validate a simple, clinically useful population-based screening test to identify at-risk athletes prior to participation in organized sports. We hypothesized that both physicians and allied health professionals would be accurate in subjectively assessing injury risk in real-time field and office conditions without motion analysis data and would be in agreement with each other. METHODS: We evaluated the inter-rater reliability of risk assessment by various observer groups, including physicians and allied health professionals, commonly involved in the care of youth athletes. Fifteen athletes age 11-17 were filmed performing a drop vertical jump test. These videos were viewed by 242 observers including orthopaedic surgeons, orthopaedic residents/fellows, coaches, athletic trainers (ATCs), and physical therapists (PTs), with the observer asked to subjectively estimate the risk level of each jumper. Objective injury risk was calculated using normalized knee separation distance (measured using Dartfish, Alpharetta, GA), based on previously published studies. Risk assessments by observers were compared to each other to determine inter-rater reliability, and to the objectively calculated risk level to determine sensitivity and specificity. Seventy one observers repeated the test at a minimum of 6 weeks later to determine intra-rater reliability. RESULTS: Between groups, the inter-rater reliability was high, κ = 0.92 (95% CI 0.829-0.969, p < 0.05), indicating that no single group gave better (or worse) assessments, including comparisons between physicians and allied health professionals. With a screening cutoff isolated to subjects identified by observers as "high risk", the sensitivity was 63.06% and specificity 82.81%. Reducing the screening cutoff to also include jumpers identified as "medium risk" increased sensitivity to 95.04% and decreased the specificity to 46.07%. Intra-rater reliability was moderate, κ = 0.55 (95% CI 0.49-0.61, p < 0.05), indicating that individual observers made reproducible risk assessments. CONCLUSIONS: This study supports the use of a simple, field-based observational drop vertical jump screening test to identify athletes at risk for ACL injury. Our study shows good inter- and intra-rater reliability and high sensitivity and suggests that screening can be performed without significant training by physicians as well as allied health professionals, including: coaches, athletic trainers and physical therapists. Identification of these high-risk athletes may play a role in enrollment in appropriate preventative neuromuscular training programs, which have been shown to decrease the incidence of ACL injuries in this population.

Markedly elevated intra-articular white cell count caused by gout alone.

Joint pain accompanied by erythema, swelling, and decreased range of motion is concerning for septic arthritis and typically warrants joint aspiration. The synovial fluid white blood cell count plays a central role in the decision-making process regarding these patients. Traditional teaching holds that a cell count greater than 50,000 white blood cells/µL is likely caused by infection and therefore warrants either operative intervention or serial aspiration. This report describes 2 patients with extremely high synovial fluid white blood cell counts in the absence of infection. Case 1 involved a 59-year-old man who presented to the emergency department with sudden onset of atraumatic left elbow pain and was found to have a white blood cell count of 168,500 white blood cells/µL on joint aspiration and innumerable monosodium urate crystals. The patient ultimately improved with treatment with oral prednisone, avoiding operative intervention. Case 2 involved a 69-year-old man who presented to the emergency department with acute onset of atraumatic left knee pain. On arthrocentesis, the patient had a cell count of 500,000 white blood cells/µL and was therefore taken to the operating room for arthroscopic irrigation and debridement. Final analysis of the synovial fluid showed monosodium urate crystals and negative culture findings. These cases illustrate the highest synovial fluid white blood cell count reported in patients with gout and highlight the potential difficulty in differentiating between acute gout and septic arthritis in the setting of markedly elevated white blood cell count.