Daniel P. O’Connor

Delayed Anterior Cruciate Ligament Reconstruction in Adolescents With Open Physes

Background Treatment of anterior cruciate ligament rupture in adolescents with open physes is controversial. Hypothesis Delaying reconstruction until the physes bridge will affect the rate of additional knee injuries. Study Design Case control. Methods The physes group was 13 adolescents with open physes whose anterior cruciate ligament reconstructions were delayed until their physes bridged. Specific types of activity were absolutely restricted during the delay. The physes groups’ rates of additional injuries, identified arthroscopically at reconstruction, were compared to rates among 116 skeletally mature adolescents. The comparison adolescents were stratified into four groups by interval from injury to reconstruction (< 1 week, 1 to 6 weeks, 6 to 26 weeks, >26 weeks). Results The additional injury rates in the physes and four comparison groups were 46%, 50%, 47%, 43%, and 69%, respectively. Severity of additional injury, mechanism of injury, and rate of additional surgical procedures were similar among the groups. Conclusions There was no evidence that intentionally delayed anterior cruciate ligament reconstruction increased the rate of additional knee injuries. Delayed reconstruction is a valid treatment option for adolescents with open physes at injury. Absolute activity restriction is key to decreasing the risk of additional knee injuries.

Indications for Reverse Total Shoulder Arthroplasty in Rotator Cuff Disease

BackgroundReverse total shoulder arthroplasty (RTSA) was introduced to treat rotator cuff tear arthropathy but is now used to treat a variety of problems. Although its use has expanded substantially since the FDA’s approval in 2004, the appropriateness in patients with rotator cuff disease is unclear.Questions/purposesWe review the use of RTSA in patients with rotator cuff disease to (1) describe classification of rotator cuff tear reparability and the concept of a balanced shoulder; (2) explore the theory behind RTSA design relative to rotator cuff arthropathy; (3) discuss the indications and contraindications for RTSA; and (4) review published outcomes of RTSA for rotator cuff arthropathy.MethodsWe performed a selective review of the literature on the use of RTSA in the treatment of rotator cuff disease.ResultsModern RTSA designs restore deltoid tension and a functional fulcrum to the rotator cuff deficient shoulder, which allows recovery of active shoulder elevation and effectively restores function in short- and medium-term followup studies.ConclusionsIn short-term followup the RTSA relieves symptoms and restores function for patients with cuff tear arthropathy and irreparable rotator cuff tears with pseudoparalysis (preserved deltoid contraction but loss of active elevation). Severely impaired deltoid function, an isolated supraspinatus tear, and the presence of full active shoulder elevation with a massive rotator cuff tear and arthritis are contraindications to RTSA.Clinical RelevanceFor properly selected patients who have symptomatic and disabling rotator cuff deficiency, RTSA can result in life-changing improvements in pain, motion, function, and patient satisfaction.Level of EvidenceLevel V therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Inferior tilt of the glenoid component does not decrease scapular notching in reverse shoulder arthroplasty: results of a prospective randomized study

HYPOTHESIS The purpose of this study was to determine if inferior tilt of the glenoid component decreased the amount of radiographic scapular notching after reverse shoulder arthroplasty. A secondary goal was to determine if inferior tilt had any effect on clinical outcome. MATERIALS AND METHODS A prospective randomized trial of 52 consecutive reverse shoulder arthroplasties performed by 1 surgeon for cuff tear arthropathy was performed. The subjects were randomly assigned to receive a glenoid component with no inferior tilt (control group) or a glenoid component that was inferiorly tilted 10° to protect the inferior glenoid (inferior tilt group). All glenoid components were placed in 3 mm of inferior translation. Radiographic notching was graded at a minimum of 1 year after surgery. Clinical outcomes of the groups were recorded. RESULTS Follow-up radiographs and data were available for 42 subjects, 20 in the inferior tilt group and 22 in the control group. The experimental groups did not differ significantly in the notch ratings or clinical outcomes. Notching occurred in 15 patients (75%) in the inferior tilt group and in 19 (86%) in the control group. Notching scores were 2 or greater in 10 patients (50%) in the inferior tilt group and in 11 (50%) in the control group. CONCLUSION Placing the glenoid component with inferior tilt does not reduce the incidence or severity of radiographic scapular notching after reverse shoulder arthroplasty. No clinical differences were observed between the groups.

Aerobic fitness is associated with lower proportions of senescent blood T-cells in man ☆

Senescent T-cells accumulate with age, lowering the naïve T-cell repertoire and increasing host infection risk. As this response is likely to be influenced by certain lifestyle factors, we examined the association between aerobic fitness (VO(2max)) and the age-related accumulation of senescent T-cells. Blood lymphocytes from 102 healthy males (18-61 yr) were analyzed for KLRG1, CD57, CD28, CD45RA, CD45RO surface expression on CD4+ and CD8+ T-cells by 4-color flow cytometry. Advancing age (yr) was positively associated with the proportion (%) of senescent (KLRG1+/CD57+; KLRG1+/CD28-) CD4+ (B=1.00; 1.02) and CD8+ (B=0.429; 1.02) T-cells and inversely associated with naïve (KLRG1-/CD28+) CD4+ (B=-1.000) and CD8+ (B=-0.993) T-cells. VO(2max) was inversely associated with senescent CD4+ (B=-0.97) and CD8+ (B=-0.240). Strikingly, age was no longer associated with the proportions of senescent or naïve T-cells after adjusting for VO(2max), while the association between VO(2max) and these T-cell subsets withstood adjustment for age, BMI and percentage body fat. Ranking participants by age-adjusted VO(2max) revealed that the highest tertile had 17% more naïve CD8+ T-cells and 57% and 37% less senescent CD4+ and CD8+ T-cells, respectively, compared to the lowest tertile. VO(2max) was not associated with latent cytomegalovirus (CMV), Epstein-Barr virus (EBV) or herpes simplex virus-1 (HSV-1) infection, indicating that the moderating associations of VO(2max) were not confounded by persistent viral infections. This is the first study to show that aerobic fitness is associated with a lower age-related accumulation of senescent T-cells, highlighting the beneficial effects of maintaining a physically active lifestyle on the aging immune system.

Longitudinal Algorithms to Estimate Cardiorespiratory Fitness Associations With Nonfatal Cardiovascular Disease and Disease-Specific Mortality

OBJECTIVES This study sought to determine the capacity of cardiorespiratory fitness (CRF) algorithms without exercise testing to predict the risk for nonfatal cardiovascular disease (CVD) events and disease-specific mortality. BACKGROUND Cardiorespiratory fitness (CRF) is not routinely measured, as it requires trained personnel and specialized equipment. METHODS Participants were 43,356 adults (21% women) from the Aerobics Center Longitudinal Study, followed up between 1974 and 2003. Estimated CRF was determined on the basis of sex, age, body mass index, waist circumference, resting heart rate, physical activity level, and smoking status. Actual CRF was measured by a maximal treadmill test. Risk reduction per 1-metabolic equivalent increase, discriminative ability (c statistic), and net reclassification improvement were determined. RESULTS During a median follow-up of 14.5 years, 1,934 deaths occurred, 627 due to CVD. In a subsample of 18,095 participants, 1,049 cases of nonfatal CVD events were ascertained. After adjustment for potential confounders, both measured and estimated CRF were inversely associated with risks for all-cause mortality, CVD-related mortality and nonfatal CVD events in men, and all-cause mortality and nonfatal CVD events in women. The risk reduction per 1-metabolic equivalent increase ranged from approximately 10% to 20%. Measured CRF had a slightly better discriminative ability (c statistic) than did estimated CRF, and the net reclassification improvement values in measured CRF versus estimated CRF were 12.3% in men (p < 0.05) and 19.8% in women (p < 0.001). CONCLUSIONS These CRF algorithms utilized information routinely collected to obtain an estimate of CRF, which provides a valid indication of health status. In addition to identifying people at risk, this method can provide more appropriate exercise recommendations that reflect initial CRF levels.

The devastating effects of tibial nonunion on health-related quality of life.

BACKGROUND Tibial nonunion is disabling, but to our knowledge no quantitative evaluation of its effect on health-related quality of life has been reported. METHODS We evaluated 243 tibial shaft fracture nonunions in 237 consecutive patients (seventy-nine female [age, 49.4 ± 14.9 years] and 158 male [age, 46.3 ± 15.4 years]) who were referred to a single surgeon at our tertiary care center over a ten-year period. The most frequently affected tibial segment was the distal third (49%), and infection was present in 18% of all cases. RESULTS The Short Form (SF)-12 Physical Component Summary score averaged 27.4 ± 6.7, indicating an extremely disabling effect on physical health. The AAOS (American Academy or Orthopaedic Surgeons) Lower Limb Core Scale score averaged 52.0 ± 19.4, also consistent with high levels of physical disability attributable to the lower limb. The SF-12 Mental Component Summary score averaged 42.3 ± 7.1, indicating a substantial detrimental effect on mental health. CONCLUSIONS The impact of tibial shaft fracture nonunion on physical health was comparable with the reported impact of end-stage hip arthrosis and worse than that of congestive heart failure. Tibial shaft fracture nonunion is a devastating chronic medical condition that negatively affects both physical and mental health and quality of life.

Exercise Dose, Exercise Adherence, and Associated Health Outcomes in the TIGER Study.

PURPOSE To effectively evaluate activity-based interventions for weight management and disease risk reduction, objective and accurate measures of exercise dose are needed. This study examined cumulative exercise exposure defined by HR-based intensity, duration, and frequency as a measure of compliance with a prescribed exercise program and a predictor of health outcomes. METHODS One thousand one-hundred fifty adults (21.3 ± 2.7 yr) completed a 15-wk exercise protocol consisting of 30 min·d, 3 d·wk, at 65%-85% maximum HR reserve. Computerized HR monitor data were recorded at every exercise session (33,473 valid sessions). To quantify total exercise dose, duration for each session was adjusted for average exercise intensity (%HR reserve) to create a measure of intensity minutes for each workout, which were summed over all exercise sessions to formulate an HR physical activity score (HRPAS). Regression analysis was used to examine the relation between HRPAS and physiological responses to exercise training. Compliance with the exercise protocol based on achievement of the minimum prescribed HRPAS was compared with adherence defined by attendance. RESULTS On the basis of HRPAS, 868 participants were empirically defined as compliant, and 282 were noncompliant. HRPAS-based and attendance-based classifications of compliance and adherence differed in approximately 9% of participants. Higher HRPAS was associated with significant positive changes in body mass (P < 0.001), body mass index (P < 0.001), waist and hip circumferences (P < 0.001), percent body fat (P < 0.001), systolic blood pressure (P < 0.011), resting HR (P < 0.003), fasting glucose (P < 0.001), and total cholesterol (P < 0.02). Attendance-based adherence was associated with body mass, hip circumference, percent body fat, resting HR, and cholesterol (P < 0.05). CONCLUSIONS The HRPAS is a quantifiable measure of exercise dose associated with improvement in health indicators beyond that observed when adherence is defined as session attendance.

Interaction of support surface stability and Achilles tendon vibration during a postural adaptation task

Orchestration of sensory-motor information and adaptation to internal or external, acute or chronic changes is one of the fundamental features of human postural control. The postural control system is challenged on a daily basis, and displays a remarkable ability to adapt to both long and short term challenges. To explore the interaction between support surface stability and Achilles tendon vibration during a period of adaptation we used both a linear measure and a non-linear measure derived from center-of-pressure (COP) data. An equilibrium score (ES), based upon peak amplitude of anterior-posterior sway towards theoretical limits of stability was the linear measure used to assess postural performance. We observed early effects of vibration on postural stability, depending on support characteristics. Participants were able to decrease sway with extended practice over days, independent of support surface stability. Approximate entropy analysis of COP data provided additional information about control adaptation processes.

Time Trade-Off as a Measure of Health-Related Quality of Life: Long Bone Nonunions Have a Devastating Impact.

BACKGROUND Long bone nonunions have an important impact on a patients quality of life. The purpose of this study was to compare long bone nonunions with use of the Time Trade-Off direct measure to compute utility scores and to determine which nonunion anatomic location had the lowest health-related quality of life. The Time Trade-Off assesses the percentage of a patients remaining life that the patient would be willing to trade for perfect health. METHODS Eight hundred and thirty-two consecutive long bone nonunions with Time Trade-Off data were identified and were retrospectively studied from a prospectively collected patient database. Nonunions with infections and those involving the articular portion of the bone were recorded. Time Trade-Off utility scores were obtained for all nonunion cases upon their initial clinical evaluation by a single surgeon specializing in reconstructive trauma. RESULTS The mean utility score of our nonunion cohort was 0.68 and it differed significantly by long bone (p = 0.037). Nonunions of the forearm had the lowest utility score (0.54), followed by the clavicle (0.59), femur (0.68), tibia or fibula (0.68), and humerus (0.71). Post hoc tests showed that patients with nonunions of the forearm had significantly lower utility scores (p = 0.031) compared with all other bones. CONCLUSIONS Patients diagnosed with a long bone nonunion have a very low health-related quality of life. We found that this single cohorts mean utility score was 0.68. This result is well below that of illnesses such as type-I diabetes mellitus (0.88), stroke (0.81), and acquired immunodeficiency syndrome (0.79). We found that patients with forearm nonunions had the lowest utility scores. LEVEL OF EVIDENCE Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Dichotomous effects of latent CMV infection on the phenotype and functional properties of CD8+ T-cells and NK-cells

CMV markedly alters the phenotype and function of NK-cells and T-cells and has been linked to immunosenescence. We show here that subjects with effective CMV control (evidenced by low CMV IgG titers) have functional responses to CMV that are driven by either NKG2C+ NK-cells or CMV-specific T-cells (15 of 24 subjects), but not both. These data indicate that people with effective CMV control are either NK-cell or T-cell responders, and corroborates the idea that NK-cells have rheostat-like properties that regulate anti-viral T-cell responses. Whether or not lifelong CMV control through either NK-cell or T-cell responses have implications for immunosenescence remains to be determined.