Post-operative urinary retention after lower extremity arthroplasty and the peri-operative role of selective alpha-1 adrenergic blocking agents in adult male patients: a propensity-matched retrospective cohort study.

PURPOSE: The purpose of this study was to determine whether male patients taking pre-operative selective alpha-1 adrenergic blocking agents have a lower likelihood of developing post-operative urinary retention (POUR) and a shorter length of hospitalization following lower extremity arthroplasty. METHODS: A retrospective cohort study was conducted of patients who underwent primary or revision total hip or knee arthroplasty, or unicompartmental knee arthroplasty at an academic institution from January 2002 to May 2014. A cohort of male patients aged 35 and older who were taking a selective alpha-1 blocker prior to surgery (N = 229) were compared with a control group (N = 330) not taking one of these medications. Propensity score-matched logistic regression was performed to isolate the effect of taking a selective alpha-1 blocker on POUR. RESULTS: When evaluating for the outcome of POUR while controlling for age, hypertension, benign prostatic hyperplasia, urinary tract infections, type of anaesthesia, and procedure, those patients taking an alpha-1 blocker had a 12.1% decreased relative risk (95% CI 3.4 to 20.8%; p = 0.007) of developing POUR compared with patients not taking these medications. Mean length of stay was 3.8 days (95% CI 3.6 to 4.1) in the cohort taking selective alpha-1 blockers compared with 4.7 days (95% CI 4.4 to 4.9) for the control cohort. CONCLUSIONS: After controlling for known risk factors for the development of POUR, the use of selective alpha-1 blockers pre-operatively reduces the risk of developing urinary retention after lower extremity arthroplasty and is associated with a 1-day decreased length of stay.

The AAHKS Clinical Research Award: Prophylactic Tamsulosin Does Not Reduce the Risk of Urinary Retention Following Lower Extremity Arthroplasty: A Double-Blinded Randomized Controlled Trial.

BACKGROUND: Postoperative urinary retention (POUR) is common. Selective alpha-1 adrenergic antagonists, such as tamsulosin, are effective for treating urinary retention. The purpose of this study is to determine whether perioperative prophylactic tamsulosin reduces the incidence of POUR following total hip and knee arthroplasty. METHODS: Male patients 35 years of age and older undergoing primary total hip or knee arthroplasty at a single center from 2015 to 2018 were eligible for inclusion. Patients were randomized to receive tamsulosin 0.4 mg or placebo daily for 5 days preoperatively, the morning of surgery, and the first postoperative day. The incidence of POUR was determined during the postoperative hospitalization. RESULTS: A total of 176 patients were enrolled in the study. Two patients were withdrawn prior to randomization. The remaining 174 were randomized to tamsulosin (n = 87) or placebo (n = 87). After an additional 43 patients were withdrawn prior to surgery, 131 patients completed the study (tamsulosin, n = 64; placebo, n = 67). A total of 42 patients (32.1%) developed POUR, with 18 cases (28.1%) in the tamsulosin group and 24 cases (35.8%) in the placebo group (P = .345), resulting in an odds ratio of 0.701 and a risk difference of 7.69%. CONCLUSION: Prophylactic tamsulosin did not reduce the incidence of POUR after hip and knee arthroplasty compared to placebo. The odds ratio indicates an approximately 30% decreased odds of developing POUR in the tamsulosin group, albeit not statistically significant. Tamsulosin does not appear to be effective as a prophylactic measure for reducing POUR in male hip and knee arthroplasty patients.

Youth Pitcher Fatigue: Medial Elbow Laxity, Ultrasonographic Assessment of Flexor-Pronator Mass Energy Depletion, and Association With Pitch Count.

Background: Ulnar collateral ligament (UCL) injuries in youth pitchers continue to be concerning despite the institution of pitch count limits. Flexor-pronator mass fatigue can lead to diminished dynamic stability, resulting in greater stress on the UCL. Purpose/Hypothesis: To evaluate fatigue of the flexor-pronator mass by assessing changes in medial elbow laxity; noninvasively characterizing alterations in muscle glycogen; and identifying changes in subjective fatigue, strength, range of motion (ROM), pitching velocity, and accuracy with increasing pitches thrown by youth pitchers to their recommended 75-pitch count limit. It was hypothesized that, with increased pitches, medial elbow laxity would increase and that the glycogen content of the flexor-pronator mass would decrease. Study Design: Descriptive laboratory study. Methods: Healthy male pitchers aged 10 years (n = 22) threw 3 sets of 25 pitches with 12 minutes between sets (3 timepoints). Bilateral ulnohumeral joint gapping was measured by applying a standardized valgus force and utilizing ultrasound imaging. Relative changes in muscle glycogen in the bilateral flexor carpi radialis (FCR), and the flexor digitorum superficialis/flexor carpi ulnaris (FDS/FCU) muscles were measured with ultrasound software and recorded as fuel percentiles. Additional measures obtained included subjective fatigue, strength, ROM, velocity, and accuracy. Results: There were no differences in medial elbow joint-line gapping between the throwing and nonthrowing arms or between timepoints. The throwing arm demonstrated a significant decline in fuel percentile of the FCR from baseline to after 75 pitches (P = .05). There were no differences across timepoints for FDS/FCU fuel percentile values. Fatigue measurements for both arms were significantly higher at all timepoints compared with baseline (P≤ .03). Grip strength of the dominant arm after 75 pitches was decreased significantly compared with after 25 pitches (P = .02). Conclusion: Although an increase in medial elbow joint gapping was not demonstrated within the recommended 75 pitch count limit in 10-year-olds, a relative decrease in glycogen stores of the flexor-pronator mass did occur, as well as a decrease in grip strength, with increasing subjective fatigue. Clinical Relevance: This study provides a foundation for further objective testing of physiologic changes that occur with pitching to better guide pitch count limits and improve the safety of young athletes.

Varied anatomy of the thumb pulley system: implications for successful trigger thumb release.

PURPOSE: The anatomical arrangement of the thumb pulley system continues to be revised through ongoing investigative research, changing our previous assumptions. This study demonstrates the components and anatomical features of this pulley system in an effort to improve surgical outcomes and to clarify current misconceptions. METHODS: Researchers procured 75 hand specimens from 41 adult cadavers through our institution's anatomical donations program. Dissections of the thumb and thenar compartment identified the various pulleys. A detailed analysis of the thumb pulleys was performed through various measurements. RESULTS: Four different pulley categories were identified: type I (n = 5), type II (n = 29), type III (n = 29), and type IV (n = 12). The variable annular pulley was present in 70 of 75 hands (93%) in 1 of 3 arrangements: transverse, oblique, or fused with the A1 pulley. CONCLUSIONS: The pulley system of the thumb is composed of 4 components, as opposed to the traditional view of only 3. Along with the A1 pulley, the additional variable annular pulley might contribute to stenosis in trigger thumb. This might necessitate a more extensive surgical incision and its partial release to relieve triggering. CLINICAL RELEVANCE: Understanding the anatomical configuration of the thumb pulley system will aid in the surgical attempt to resolve triggering while avoiding complications such as bowstringing of the flexor pollicis longus tendon and iatrogenic nerve injury.

Reduced Myogenic and Increased Adipogenic Differentiation Capacity of Rotator Cuff Muscle Stem Cells.

BACKGROUND: Fat accumulation commonly occurs in chronically torn rotator cuff muscles, and increased fat within the rotator cuff is correlated with poor clinical outcomes. The extent of lipid deposition is particularly pronounced in injured rotator cuff muscles compared with other commonly injured muscles such as the gastrocnemius. Satellite cells, which are a tissue-resident muscle stem-cell population, can differentiate into fat cells. We hypothesized that satellite cells from the rotator cuff have greater intrinsic adipogenic differentiation potential than do gastrocnemius satellite cells, and this difference is due to variations in epigenetic imprinting between the cells. METHODS: Satellite cells from gastrocnemius and rotator cuff muscles of mice were cultured in adipogenic media, and the capacity to differentiate into mature muscle cells and adipogenic cells was assessed (n ≥ 9 plates per muscle group). We also performed DNA methylation analysis of gastrocnemius and rotator cuff satellite cells to determine whether epigenetic differences were present between the 2 groups (n = 5 mice per group). RESULTS: Compared with the gastrocnemius, satellite cells from the rotator cuff had a 23% reduction in myogenic differentiation and an 87% decrease in the expression of the differentiated muscle cell marker MRF4 (myogenic regulatory factor 4). With respect to adipogenesis, rotator cuff satellite cells had a 4.3-fold increase in adipogenesis, a 12-fold increase in the adipogenic transcription factor PPARγ (peroxisome proliferator-activated receptor gamma), and a 65-fold increase in the adipogenic marker FABP4 (fatty-acid binding protein 4). Epigenetic analysis identified 355 differentially methylated regions of DNA between rotator cuff and gastrocnemius satellite cells, and pathway enrichment analysis suggested that these regions were involved with lipid metabolism and adipogenesis. CONCLUSIONS: Satellite cells from rotator cuff muscles have reduced myogenic and increased adipogenic differentiation potential compared with gastrocnemius muscles. There appears to be a cellular and genetic basis behind the generally poor rates of rotator cuff muscle healing. CLINICAL RELEVANCE: The reduced myogenic and increased adipogenic capacity of rotator cuff satellite cells is consistent with the increased fat content and poor muscle healing rates often observed for chronically torn rotator cuff muscles. For patients undergoing rotator cuff repair, transplantation of autologous satellite cells from other muscles less prone to fatty infiltration may improve clinical outcomes.