Altered Knee Loading Following Primary ACL Repair versus ACL Reconstruction

Background

ACL repair (ACL-r) has recently gained renewed clinical interest for treatment of ACL tears. ACL-r has several potential benefits over ACL reconstruction (ACL-R) including maintaining the native ACL innervation and blood supply, no graft site morbidity, and possible improved knee biomechanics and decrease in osteoarthritis. The purpose of this study was to assess for differences in metrics of knee joint loading during a single limb squat task between individuals following a primary ACL-r versus those who underwent a standard ACL-R with a patella bone-tendon-bone autograft.

Study type

Case Control Study.

Methods

The ACL-r group [n: 15, age(yrs): 38.8±13.9] sustained a proximal ACL disruption that was amenable to repair, while the ACL-R group [n: 15, age(yrs): 25.60±1.7] underwent primary reconstruction with patella bone-tendon-bone autograft. At 12-weeks post-operation, both groups completed the IKDC questionnaire and biomechanical testing during performance of the single limb squat. Bilateral peak knee extension moment and total knee joint power as a measure of eccentric loading (contraction) during the descent phase of the squat were calculated on the surgical and non-surgical limb and averaged across the middle three of five trials. Participants also completed quadriceps strength testing on both limbs three months after surgery on an isokinetic dynamometer at 60°/sec. LSI (Limb Strength Index) was calculated for all variables. Separate ANCOVAs were performed on each biomechanical variable to examine differences between groups.

Results

The ACL-r had a significantly greater peak knee extension moment LSI (ACL-r: 78.46±5.79%; ACL-R: 56.86±5.79%; p=0.019, ηp2=.186) and total knee joint power LSI (ACL-r: 72.47±7.39%; ACL-R: 39.70±7.39%, p=0.006, ηp2=.245) than the ACL-R group. The ACL-r also had a significantly greater quadriceps LSI than the ACL-R group (ACL-r: 66.318±4.61%, ACL-R: 48.03±4.61%, p=0.013, ηp2=.206).

Conclusions

Individuals following ACL-r demonstrate increased knee joint loading symmetry during a single leg squat task and greater quadriceps strength symmetry at 12 weeks post-surgery compared to those who underwent ACL-R.

Level of Evidence

3.

Adolescent Athletes Demonstrate Inferior Objective Profiles at the Time of Return to Sport After ACLR Compared With Healthy Controls

Background:

Athletes display persistent muscle deficits and altered limb-loading mechanics at the time of return to sport (RTS) after anterior cruciate ligament reconstruction (ACLR).

Purpose:

To compare an objective profile of adolescent athletes at RTS after ACLR to matched healthy controls.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Included were 124 participants; 62 patients who underwent ACLR (15.4 ± 1.7 years) and 62 healthy controls (15.3 ± 1.7 years). Motion capture and force plates were used to capture joint motions during jump landing (JL) and single-limb squat (SLS) tasks. Energy absorption contribution (EAC) was calculated, and repeated-measures analysis of variance was used to assess for EAC differences between groups. Participants completed an International Knee Documentation Committee (IKDC) Subjective Knee Form, and isokinetic quadriceps and hamstring strength testing was performed on each limb. Independent t tests were run to examine age, height, weight, and IKDC scores as well as compare differences between groups for quadriceps and hamstring strength.

Results:

A significant group × joint interaction was found for JL (P < .001) and SLS (P < .001). For JL, patients who underwent ACLR utilized significantly greater hip (P < .001) and significantly less knee (P < .001) EAC on the surgical limb compared with controls. During SLS, patients who underwent ACLR utilized significantly greater hip (P < .001) and significantly less knee (P < .001) EAC on the surgical limb compared with controls. The ACLR cohort demonstrated lower IKDC scores (P < .001) and significantly lower quadriceps strength on the surgical limb (P < .001) than controls. There were no differences in surgical limb hamstring strength between the ACLR cohort and healthy controls (P = .701).

Conclusion:

Compared with matched healthy controls, the participants who underwent ACLR in this study demonstrated an inferior objective profile at RTS, consisting of deficits in surgical limb loading, self-reported outcomes, and strength.

Limb dominance influences energy absorption contribution (EAC) during landing after anterior cruciate ligament reconstruction

OBJECTIVE

To determine the role of limb dominance on energy absorption contribution (EAC) during a jump landing (JL) task at return to sport (RTS) after ACL-R.

DESIGN

Cross-sectional study.

SETTING

Clinical Research Laboratory.

PARTICIPANTS

One hundred eight participants (age = 16.19 ± 1.74, Height = 172.25 ± 9.96 cm, Weight = 72.61 ± 15.48 kg).

MAIN OUTCOME MEASURES

Participants were grouped into two groups: those who injured their dominant limb ACL (D-ACL) and those who injured their non-dominant limb ACL (ND-ACL). A multiple analysis of variance (MANOVA) was used to assess for between group differences in EAC across the three joints.

RESULTS

In the surgical limb, D-ACL demonstrated smaller hip (D-ACL = 32.23 ± 10.44%, ND-ACL = 69.68 ± 8.51%, p < 0.008) and greater knee (D-ACL = 45.86 ± 10.36%, ND-ACL = 9.41 ± 5.68%, p < 0.008) EAC than ND-ACL. In the non-surgical limb, D-ACL demonstrated greater hip (D-ACL = 62.59 ± 9.03%, ND-ACL = 25.95 ± 7.15%, p < 0.008), and smaller knee (D-ACL = 13.79 ± 5.57%, ND-ACL = 58.01 ± 7.86%, p < 0.008), EAC than ND-ACL.

CONCLUSION

After ACL-R, eccentric loading strategies during a JL task at RTS are different depending upon limb dominance. D-ACL demonstrated a greater knee loading strategy on the surgical side compared to ND-ACL.

MOVEMENT PATTERNS DIFFER BETWEEN ATHLETES AFTER SPORT-RELATED CONCUSSION COMPARED TO HEALTHY CONTROLS DURING JUMP LANDING TASK

CONTEXT

A relationship between a positive history of sport-related concussion (SRC) and lower extremity (LE) injury has been well established in the literature.

OBJECTIVE

The purpose of this study was to determine if biomechanical differences exist during a double limb jump landing (DLJ) between athletes who had been released for return to play after SRC and healthy matched controls (Healthy).

DESIGN

Cross-Sectional Study Setting: Health system-based Outpatient Sports Medicine Center Participants: 21 participants (16.33±12.7 days out from being released to return to sport after SRC) (age: 15.38±1.77; height: 169.23±8.59; mass: 63.43±7.39) were compared to 21 age, sex, activity-matched healthy controls (age: 15.36±1.73; height: 169.92±11.1; mass: 65.62±12.08). No significant differences existed between groups for descriptive data.

MAIN OUTCOME MEASURE(S)

Biomechanical performance during DLJ was assessed using Motion Capture System and force plates. The average of five consecutive trials was used to calculate lower extremity joint kinetic and kinematics. Variables of interest included internal knee extension moment, internal varus moment, and total sagittal plane knee displacement for both the dominant and non-dominant limbs. Independent t-tests were performed to examine the differences between SRC and Healthy groups for variables of interest.

RESULTS

The SRC group demonstrated greater internal knee extension moments on their dominant (KEDomDiff=-.028±.009; p=.003) and non-dominant (KENonDomDiff=-.018±.007, p=.019) limbs. The SRC group also demonstrated greater internal varus moments on their dominant (VDomDiff=.012±.004, p=.005) and non-dominant (VNonDomDiff=.010±.003, p=.005) limbs. For sagittal plane knee displacement, the SRC group demonstrated less knee flexion displacement on their dominant (DispDomDiff=-12.56±4.67, p=.011) but not their non-dominant limb (DispNonDomDiff=-8.30±4.91, p=.099).

CONCLUSIONS

Athletes who have been released for return to sport after SRC land in greater knee valgus compared to healthy matched controls.

Thigh-Muscle and Patient-Reported Function Early After Anterior Cruciate Ligament Reconstruction: Clinical Cutoffs Unique to Graft Type and Age

CONTEXT

Patient-reported function is an important outcome in anterior cruciate ligament rehabilitation. Identifying which metrics of thigh-muscle function are indicators of normal patient-reported function can help guide treatment.

OBJECTIVE

To identify which metrics of thigh-muscle function discriminate between patients who meet and patients who fail to meet age- and sex-matched normative values for patient-reported knee function in the first 9 months after anterior cruciate ligament reconstruction (ACLR) and establish cutoffs for these metrics by covariate subgroups.

DESIGN

Cross-sectional retrospective study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 256 patients (129 females, 128 males; age = 17.1 ± 3.0 years, height = 1.7 ± 0.1 m, mass = 74.1 ± 17.9 kg, months since surgery = 6.4 ± 1.4), 3 to 9 months after primary unilateral ACLR.

MAIN OUTCOME MEASURE(S)

We stratified the sample into dichotomous groups by the International Knee Documentation Committee (IKDC) score (IKDCMET, IKDCNOT MET) using sex- and age-matched normative values. We measured quadriceps and hamstrings isokinetic (60°/s) torque and power bilaterally. Normalized quadriceps and hamstrings peak torque (Nm/kg) and power (W/kg), limb symmetry indices (LSI, %), and hamstrings : quadriceps ratios were calculated. Logistic regression indicated which of these metrics could predict IKDC classification while controlling for age, graft type, and sex. Receiver operating characteristic curves established cutoffs for explanatory variables for both total cohort and covariate subgroups. Odds ratios (OR) determined the utility of each cutoff to discriminate IKDC status.

RESULTS

Quadriceps torque LSI (≥69.4%, OR = 3.6), hamstrings torque (≥1.11 Nm/kg, OR = 2.1), and quadriceps power LSI (≥71.4%, OR = 2.0) discriminated between IKDC classification in the total cohort. Quadriceps torque LSI discriminated between IKDC classification in the patellar-tendon graft (≥61.6%, OR = 5.3), hamstrings-tendon graft (≥71.8%, OR = 10.5), and age <18 years (≥74.3%, OR = 5.2) subgroups. Hamstrings torque discriminated between IKDC classifications in the age <18 years (≥1.10 Nm/kg, OR = 2.6) subgroup.

CONCLUSIONS

Quadriceps torque LSI, hamstrings torque, and quadriceps power LSI were the most useful metrics for predicting normal patient-reported knee function early after ACLR. Further, cutoff values that best predicted normal patient-reported function differed by graft type and age.

Physical illnesses associated with childhood homelessness - a literature review

Background and aims

Childhood homelessness is a growing concern in Ireland creating a Pediatric subpopulation at increased risk of physical illnesses, many with life-long consequences. Our aim was to identify and categorize the physical morbidities prevalent in homeless children.

Methods

A review of the English-language literature on physical morbidities affecting homeless children (defined as &lt; 18 years of age), published from 1999-2019 was conducted. A total of 1194 articles were identified, 33 articles of which met our inclusion criteria.

Results

Respiratory issues were the most commonly cited illnesses affecting homeless children; including asthma, upper respiratory tract infections, and chronic cough. Homeless children were described as being at increased risk of contracting infectious diseases, many studies placing emphasis on STI and HIV/AIDS transmission. Dermatologic concerns comprised of scabies and head lice infestation, dermatitis, and abrasions. Malnutrition manifested as a range of physical morbidities; including childhood obesity, iron deficiency anemia, and stunted growth. Studies found a higher prevalence of poor dental and ocular health in this population as well. Many articles also commented on the risk factors predisposing homeless children to these physical health concerns, which can broadly be categorized as limited access to health care, poor living conditions, and lack of education.

Conclusions

This literature review summarized the physical illnesses prevalent among homeless children and the contributing factors leading to them. Gaps in the literature were also identified, and included a dearth of studies focusing on younger children compared to adolescents. We believe that the current issue of child homelessness is socially and medically unacceptable and that homelessness occurring today will be one of the scandals of the next generation. Further research into prevention and intervention programs for this vulnerable population is urgently needed.

Key messages

This literature review shows that homeless children are at an increased risk of several physical morbidities and identified the common themes among them. Based on this literature review, it is recommended that more research be done into developing appropriate intervention and prevention strategies to help this vulnerable population.

NO DIFFERENCES IN HIP RANGE OF MOTION EXISTS BETWEEN BASEBALL PLAYERS WITH AN ULNAR COLLATERAL LIGAMENT TEAR AND HEALTHY BASEBALL PLAYERS

BACKGROUND AND PURPOSE

Restrictions in hip rotational motion of the baseball athlete can alter throwing mechanics in a manner that is inefficient and increases risk of injury. The purpose of this study was to assess for differences in hip external rotation (ER) and internal rotation (IR) range of motion (ROM) between baseball players with an ulnar collateral ligament (UCL) tear and healthy baseball players.

DESIGN

Case-control.

METHODS

Eighty-seven baseball players with a UCL tear (UCL) were compared with 87 age, experience, and position-matched healthy baseball players (CONT). UCL were enrolled at the initial visit to the outpatient sports medicine facility while CONT were measured before their baseball season. Passive hip ROM (ER and IR) of the stance and lead limbs was measured in the prone position using a bubble goniometer. Hip total range of motion (TRM) was calculated by adding ER and IR of each limb. Independent t-tests were run to compare mean group differences for hip ROM (p<0.05).

RESULTS

No differences between groups were discovered for hip ER on the stance (UCL = 33.9 °±9.9 °, CONT = 34.3 °±10.6 °, p = 0.8) or lead (UCL = 32.9 °±9.9 °, CONT = 34.4 °±10.0 °, p = 0.3) limbs. Similarly, there were no group differences in hip IR on the stance (UCL = 30.6 °±10.5 °, CONT = 29.6 °±9.5 °, p = 0.5) or lead (UCL = 33.5 °±17.5 °, CONT = 29.5 °±9.0 °, p = 0.1) limbs. The groups were also similar in hip TRM on the stance (UCL = 64.5 °±13.7 °, CONT = 64.0 °±17.2 °, p = 0.8) and lead (UCL = 66.4 °±17.4 °, CONT = 63.9 °±15.6 °, p = 0.3) limbs.

CONCLUSIONS

When measured in the prone position, hip passive ROM is not different between baseball players with a UCL tear compared to a matched healthy cohort.

LEVEL OF EVIDENCE

Level 3.

Knee Loading After ACL-R Is Related to Quadriceps Strength and Knee Extension Differences Across the Continuum of Care

Background:

Quadriceps strength and knee extension are believed to be important in the ability to effectively load the knee after anterior cruciate ligament (ACL) reconstruction (ACL-R).

Purpose:

To compare quadriceps strength (QUADS), side-to-side knee extension difference (ExtDiff), and knee energy absorption contribution (EAC) in patients preoperatively, 12 weeks postoperatively, and at return to sport (RTS). A secondary aim was to determine how the factors of QUADS and ExtDiff contributed to the ability to load the knee (knee EAC) at each of the 3 time points.

Study Design:

Case series; Level of evidence, 4.

Methods:

Overall, 41 individuals (mean ± SD age, 15.95 ± 1.63 years) were enrolled in this study. QUADS, ExtDiff, and knee EAC during a double-limb squat were collected preoperatively, 12 weeks postoperatively, and at RTS. Isokinetic QUADS was collected at 60 deg/s, normalized to body mass, and averaged across 5 trials. Knee extension was measured with a goniometer, and ExtDiff was calculated for analyses. Knee EAC was measured during double-limb squat descent and was calculated as a percentage of total energy absorption for the limb. Observations were obtained from both the surgical and nonsurgical limbs at the 3 time points. A mixed regression model with random intercept to compare change over the 3 time points was used, and a model selection was conducted with Akaike information criteria. Significance was set at P < .05.

Results:

Surgical limb QUADS was significantly lower preoperatively (mean ± SD, 1.37 ± 0.49 N·m/kg; P = .0023) and at 12 weeks (1.11 ± 0.38 N·m/kg; P < .0001) than at RTS (1.58 ± 0.47 N·m/kg). Nonsurgical limb QUADS was also significantly lower preoperatively (2.01 ± 0.54 N·m/kg; P < .0256) and at 12 weeks (2.03 ± 0.48 N·m/kg; P < .0233) than at RTS (2.18 ± 0.54 N·m/kg). Knee EAC for the surgical limb was significantly lower at 12 weeks than at RTS (40.98% ± 13.73% vs 47.50% ± 12.04%; P < .0032), and ExtDiff was significantly greater preoperatively than at RTS (–2.68° ± 3.19° vs –0.63° ± 1.43°; P < .0001). Preoperatively, QUADS for both the surgical (P < .0003) and nonsurgical (P = .0023) limbs was a significant predictor of surgical limb knee EAC, explaining 33.99% of the variance. At 12 weeks, surgical limb QUADS was a significant predictor (P < .0051) of surgical limb knee EAC, explaining 18.83% of the variance. At RTS, ExtDiff was a significant predictor (P = .0201) of surgical limb knee EAC, explaining 12.92% of the variance.

Conclusion:

The ability to load the knee after ACL injury changes across the continuum of care and is related to QUADS and ExtDiff. These results provide clinicians with insight into potential contributing factors that may limit knee loading during the rehabilitation process.

The validity and reliability of the Vail Sport Test™ as a measure of performance following anterior cruciate ligament reconstruction

OBJECTIVES

To determine the validity and inter-session reliability of the Vail Sport Test™.

DESIGN

Cohort study-exploratory methodological research design.

SETTING

Clinical Research Laboratory.

PARTICIPANTS

Forty-eight participants who underwent ACL-R.

MAIN OUTCOME MEASURE

Participants performance on the Vail Sport Test™ was graded by an experienced rater in real-time, and simultaneously recorded by a three-dimensional (3D) motion capture system. Construct validity was assessed using the reference standards of the camera system and the IKDC short form. To determine the between-day reliability, a subset of participants returned to repeat the test.

RESULTS

There were no significant difference between the scores collected in real-time and from the kinematic data on the involved limb (p = 0.222). There was a significant difference for the uninvolved limb (p = 0.015). There was no significant difference between the scores collected in real time and those of the IKDC (p = 0.885). Good inter-session reliability (ICC = 0.787) was found for the involved limb.

CONCLUSION

The results of this study showed good reliability and partially support the validity of the Vail Sport Test as a measure of readiness to return to play.

'The genome wager' at its midpoint: Implications for developmental biology

Prediction is a very important part of the business of scientific theories, and scientists like to make wagers. Back in 2009, two prominent biologists within the public arena entered into a gentleman's bet about the explanatory value of the genome. Lewis Wolpert believes that, by 2029, it will be possible to predict all the physical details of a complex organism by the knowledge of its genome. Rupert Sheldrake, conversely, insists that new scientific principles are needed to explain development. It is also over a decade since Sean Carroll formalized the cis-regulatory hypothesis of morphological evolution. This paradigm, whereby major changes in form are produced by small variations in regulatory DNA, is congruent with Wolpert's own understanding of the genome. Research conducted over the past decade, however, suggests that a gene-centred approach to developmental evolution may be fading, but there is still much to work on. Far from being eccentric, the wager's outcome could affect the future course of the field of developmental biology.

Participants at three months post-operative anterior cruciate ligament reconstruction (ACL-R) demonstrate differences in lower extremity energy absorption contribution and quadriceps strength compared to healthy controls

BACKGROUND

The purpose of this study was to compare hip and knee energy absorption contribution (EAC) during a double limb squat (DLS) and quadriceps strength in patients three months post-operative ACL-R versus matched healthy controls.

METHODS

Twenty-four ACL-R participants (Age = 15.5 ± 1.3 yrs; Ht = 1.66 ± .07 m; Mass = 66.3 ± 15.5 kg) were compared to 24 age, sex, limb, and activity-matched healthy controls (Age = 15.5 ± 1.2 yrs; Ht = 1.65 ± .08 m; Mass = 59.0 ± 9.8 kg). Lower extremity biomechanical data was collected at three months post-operative ACL-R during five consecutive DLS. EAC was calculated during DLS descent. Isokinetic quadriceps strength was collected at 60°/s. Normalized quadriceps peak torque (QUADS) was averaged across five trials. Independent t-tests examined differences in group hip and knee EAC during each task. Separate Pearson product-moment correlations examined the relationship between QUADS and hip and knee EAC during the DLS.

RESULTS

ACL-R demonstrated greater injured limb hip EAC (46.4 ± 16.0) than Healthy (31.7 ± 11.0) during a DLS (p = 0.001). ACL-R demonstrated less injured limb knee EAC (42.7 ± 14.6) than Healthy (60.6 ± 8.9) during DLS (p < 0.001). No differences were seen between uninjured limb hip (ACL-R = 0.0 ± 14.2; Healthy = 33.4 ± 9.1, p = 0.629) or knee (ACL-R = 56.9 ± 15.6; Healthy = 59.1 ± 9.8, p = 0.561) EAC and matched limbs. ACL-R injured limb QUADS was decreased compared to Healthy (ACL-R = 1.1 ± 0.5; Healthy = 2.0 ± 0.5, p < 0.001). No differences were seen in QUADS on the uninjured and matched limbs (ACL-R = 2.0 ± 0.6; Healthy = 1.9 ± 0.5, p = 0.894). There was a weak, negative correlation between injured limb QUADS and hip EAC (r = -0.471, p = 0.001) and moderate, positive correlation between injured limb QUADS and knee EAC (r = 0.615, p < 0.001).

CONCLUSIONS

ACL-R participants demonstrate different eccentric loading strategies during a DLS at three months postoperative compared to matched healthy controls.

THE RELATIONSHIP BETWEEN PRE-OPERATIVE AND TWELVE-WEEK POST-OPERATIVE Y-BALANCE AND QUADRICEPS STRENGTH IN ATHLETES WITH AN ANTERIOR CRUCIATE LIGAMENT TEAR

BACKGROUND

Pre-operative quadriceps strength may have a positive influence on post-operative function and outcomes at time of return to sport. Little consideration has been given to quadriceps strength during the early post-operative timeframes. Twelve-week post-operative anterior cruciate ligament reconstruction (ACL-R) is considered a critical time point for progression in the rehabilitation process. There is currently limited research looking at the relationship between clinical measurements pre-operatively and at 12-weeks following ACL-R.

PURPOSE/HYPOTHESIS

The primary purpose of this study was to examine the differences between Y-Balance Test Lower Quarter (YBT-LQ) and isokinetic quadriceps strength tested pre-operatively and post-operatively following ACL-R (12-weeks).

STUDY DESIGN

Within subject, repeated measures.

METHODS

Thirty-nine participants (15.6 ± 1.5 y/o) were diagnosed with an ACL tear and were undergoing rehabilitation to return to a sport requiring cutting and pivoting were included. YBT-LQ and isokinetic quadriceps strength were assessed pre-operatively and at 12-weeks after ACL-R. YBT-LQ composite scores were calculated bilaterally and isokinetic quadriceps strength was tested using the Biodex Multi-Joint Testing and Rehabilitation System. Paired T-tests were used to determine mean group differences between YBT-LQ and isokinetic quadriceps strength scores pre-operatively and at 12-weeks post-operative. A Pearson Correlation was performed to determine relationships between variables at both time points.

RESULTS

There was a significant improvement in YBT-LQ composite scores from pre-operative to 12-weeks post-operative on both the involved (Pre-operative: 89.0 ± 7.7; 12-weeks: 94.1 ± 7.1, p<0.001) and uninvolved (Pre-operative: 92.6 ± 6.2; 12-weeks: 97.6 ± 6.8, p<0.001) limbs. Quadriceps strength decreased significantly from pre-operative to 12-weeks on the involved limb (Pre-operative: 82.3 ftlbs ± 38.6; 12-weeks: 67.9 ftlbs±27.4, p<0.01), but no differences were found on the uninvolved limb (Pre-operative: 117.3ftlbs ± 42.0; 12-weeks: 121.7ftlbs ± 41.5, p = 0.226).

CONCLUSIONS

Involved limb quadriceps strength decreases from time of pre-operative to 12-weeks following ACL-R.

LEVEL OF EVIDENCE

3.

Dynamics of silver elution from functionalised antimicrobial nanofiltration membranes

In an effort to mitigate biofouling on thin film composite membranes such as nanofiltration and reverse osmosis, a myriad of different surface modification strategies has been published. The use of silver nanoparticles (Ag-NPs) has emerged as being particularly promising. Nevertheless, the stability of these surface modifications is still poorly understood, particularly under permeate flux conditions. Leaching or elution of Ag-NPs from the membrane surface can not only affect the antimicrobial characteristics of the membrane, but could also potentially present an environmental liability when applied in industrial-scale systems. This study sought to investigate the dynamics of silver elution and the bactericidal effect of an Ag-NP functionalised NF270 membrane. Inductively coupled plasma-atomic emission spectroscopy was used to show that the bulk of leached silver occurred at the start of experimental runs, and was found to be independent of salt or permeate conditions used. Cumulative amounts of leached silver did, however, stabilise following the initial release, and were shown to have maintained the biocidal characteristics of the modified membrane, as observed by a higher fraction of structurally damaged Pseudomonas fluorescens cells. These results highlight the need to comprehensively assess the time-dependent nature of bactericidal membranes.

Do Muscle Strength Deficits of the Uninvolved Hip and Knee Exist in Young Athletes Before Anterior Cruciate Ligament Reconstruction?

Background:

Muscle strength of the involved limb is known to be decreased after injury. Comparison with the uninvolved limb has become standard of practice to measure progress and for calculation of limb symmetry indices (LSIs) to determine readiness to return to sport. However, some literature suggests strength changes in the uninvolved limb also are present after lower extremity injury.

Purpose:

To examine the uninvolved limb strength in a population of adolescent athletes after an anterior cruciate ligament (ACL) injury and compare strength values with those of the dominant limb in a healthy control group.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 64 athletes were enrolled in this study, including 31with injured ACLs (mean age, 15.6 ± 1.4 years) and 33 healthy controls (mean age, 14.9 ± 1.9 years). The median time from injury to testing was 23 days for the ACL-injured group. Participants underwent Biodex isokinetic strength testing at 60 deg/s to assess quadriceps and hamstring strength. Isometric hip strength (abduction, extension, external rotation) was measured using a handheld dynamometer. The muscle strength of the uninvolved limb of the ACL-injured group was compared with that of the dominant limb of the healthy control group.

Results:

The results showed a significant difference in quadriceps muscle strength between the 2 study groups (P < .001). Isokinetic quadriceps strength of the uninvolved limb in the ACL group was significantly decreased by 25.5% (P < .001) when compared with the dominant limb of the control group.

Conclusion:

The results of this study demonstrate a decreased isokinetic strength of the quadriceps muscle in the uninvolved limb after ACL injury as compared with healthy controls. Consideration should be taken when using the uninvolved limb for comparison when assessing quadriceps strength in a population with an ACL injury.

Evaluation, Treatment, and Rehabilitation Implications of the Infrapatellar Fat Pad

Context:

The infrapatellar fat pad (IFP) is in the anterior knee compartment and may be a major pain generator.

Evidence Acquisition:

A PubMed database search using the terms Hoffas fat pad, anterior interval, and infrapatellar fat pad was performed from the years 1970 to 2015.

Study Design:

Clinical review.

Level of Evidence:

Level 5.

Results:

Limited research exists examining the role of the IFP in relation to potential treatment and rehabilitation implications.

Conclusions:

Alterations in IFP mobility, whether the result of postsurgical scarring or faulty movement patterns, result in pain and disability in a variety of patient populations. The majority of treatment approaches are driven by the surgical technique.

Lower extremity balance is improved at time of return to throwing in baseball players after an ulnar collateral ligament reconstruction when compared to pre-operative measurements

BACKGROUND

/

PURPOSE

Lower extremity balance deficits have been shown to lead to altered kinematics and increased injury risk in lower extremity athletes. The purpose of this study was to compare lower extremity balance in baseball players with an ulnar collateral ligament (UCL) tear pre-operatively and post-operatively at the beginning of the pre-return to throwing program stage of rehabilitation (3 months).

METHODS

Thirty-three competitive high school and collegiate male baseball players (18.5 ± 3.2) with a diagnosed UCL tear volunteered for the study. Of the 33 baseball players 29 were pitchers, 1 was a catcher, and 3 were infielders. Participants were seen pre-operatively and at 3 months post operatively. This 3 month point was associated with a follow-up visit to the orthopedic surgeon and subsequent release to begin the pre-return to throwing mark for baseball players following their surgery. Following surgery, each participant followed a standard UCL protocol which included focused lower extremity balance and neuromuscular control exercises. Participants were tested for single leg balance using the Y-Balance Test™ - Lower Quadrant (YBT-LQ) on both their lead and stance limbs. YBT-LQ composite scores were calculated for the stance and lead limbs pre- and post-operatively and compared over time. Paired t-tests were used to calculate differences between time 1 and time 2 (p < 0.05).

RESULTS

Baseball players with diagnosed UCL tears demonstrated significant balance deficits on their stance (p < .001) and lead (p = .009) limbs prior to surgery compared to balance measures at the 3-month follow up (Stance Pre-Op = 89.4 ± 7.5%; Stance 3 Month = 94.9 ± 9.5%) (Lead Pre-Op = 90.2 ± 6.7%; Lead 3 Month = 93.6 ± 7.2%).

CONCLUSION

Based on the results of this study, lower extremity balance is altered in baseball players with UCL tears prior to surgery. Statistically significant improvements were seen and balance measures improved at the time of return to throwing.

LEVEL OF EVIDENCE

Level 2b.

Clinimetrics corner: a closer look at the minimal clinically important difference (MCID)

Minimal clinically important difference (MCID) scores are commonly used by clinicians when determining patient response to treatment and to guide clinical decision-making during the course of treatment. For research purposes, the MCID score is often used in sample size calculations for adequate powering of a study to minimize the false-positives (type 1 errors) and the false-negatives (type 2 errors). For clinicians and researchers alike, it is critical that the MCID score is a valid and stable measure. A low MCID value may result in overestimating the positive effects of treatment, whereas a high MCID value may incorrectly classify patients as failing to respond to treatment when in fact the treatment was beneficial. The wide range of methodologies for calculating the MCID score results in varied outcomes, which leads to difficulties with interpretation and application. This clinimetrics corner outlines key factors influencing MCID estimates and discusses limitations with the use of the MCID in both clinical and research practice settings.

Residents case report: deep vein thrombosis in a high school baseball pitcher following ulnar collateral ligament (ucl) reconstruction

BACKGROUND AND PURPOSE

Accurate diagnosis of deep vein thrombosis in an outpatient setting is difficult; however, proper screening and prompt referral can be lifesaving. The purpose of this case report is to present the unusual findings of a Deep Vein Thrombosis (DVT) in an otherwise healthy young male following an upper extremity surgery.

CASE DESCRIPTION

An 18 year-old male high school baseball pitcher presented to the clinic for his four month follow up visit after Ulnar Collateral Ligament (UCL) reconstruction surgery. Patient complained of a recent "groin strain" and "calf strain" following baseball conditioning, that upon examination demonstrated signs and symptoms consistent with a deep vein thrombosis (DVT).

OUTCOMES

Following emergent referral the patient was diagnosed with multiple emboli and was treated with Lovenox and Coumadin.

DISCUSSION

Lower extremity DVT is a serious and potentially life threatening disorder. Physical therapists need to be vigilant in their subjective and objective examination of any patient that presents with lower extremity pain and swelling. This case report presents the unlikely findings of a DVT in a young, healthy, male high school baseball pitcher after surgical repair of the UCL.

LEVEL OF EVIDENCE

4.

Evaluation of red blood cells stored at -80 degrees C in excess of 10 years

BACKGROUND

RBCs frozen in 40 percent (wt/vol) glycerol are currently approved by the FDA and the AABB for storage at -80 degrees C for up to 10 years.

STUDY DESIGN AND METHODS

This study examined 20 RBC units that had been cryopreserved in 40 percent (wt/vol) glycerol and stored at -80 degrees C for up to 22 years. Measures of the freeze-thaw-wash (FTW) recovery, ATP, 2,3-DPG, methemoglobin, RBC indices, morphology, and osmotic fragility were made immediately after deglycerolization and after 24 hours of storage at 4 degrees C.

RESULTS

RBCs frozen for longer than 10 years had acceptable mean FTW recovery, normal oxygen transport function, RBC morphology, RBC indices, methemoglobin, and osmotic fragility. Statistical analysis indicated that the in-vitro viability and function of cryopreserved RBCs was not dependent on the length of frozen storage or postthaw storage at 4 degrees C but did correlate with the storage length at 4 degrees C before cryopreservation.

CONCLUSION

The data reported in this study demonstrate that RBCs can be stored at -80 degrees C beyond 10 years with acceptable in-vitro quality and suggest that more defined criteria for the cryopreservation process be adopted.

SRA880, in vitro characterization of the first non-peptide somatostatin sst(1) receptor antagonist

This report describes the in vitro features of the first somatostatin sst(1) receptor selective non-peptide antagonist, SRA880 ([3R,4aR,10aR]-1,2,3,4,4a,5,10,10a-Octahydro-6-methoxy-1-methyl-benz[g] quinoline-3-carboxylic-acid-4-(4-nitro-phenyl)-piperazine-amide, hydrogen malonate). SRA was evaluated in a number of in vitro systems of various species, both at native and recombinant receptors, using radioligand binding and second messenger/transduction studies. SRA880 has high affinity for native rat, mouse, monkey and human cerebral cortex somatostatin sst(1) receptors (pK(d) = 7.8-8.6) and for human recombinant sst(1) receptors (pK(d) = 8.0-8.1). SRA880 displayed significantly lower affinity for the other human recombinant somatostatin receptors ( pK(d) < or = 6.0) or a wide range of neurotransmitter receptors, except for the human dopamine D4 receptors. SRA880 was characterized in various transduction assays: somatotropin release inhibiting factor (SRIF) induced inhibition of forskolin-stimulated cAMP accumulation, SRIF stimulated-GTPgammaS binding, and SRIF stimulated luciferase gene expression; in all tests, SRA880 was devoid of intrinsic activity and acted as an apparently surmountable antagonist with pK(B) values of 7.5-7.7. Combined with the data from binding studies, these results suggest that SRA880 acts as a competitive antagonist. Thus, SRA880 is the first non-peptide somatostatin sst(1) receptor antagonist to be reported; SRA880 will be a useful tool for the characterization of somatostatin sst(1) receptor-mediated effects both in vitro and in vivo.

Damage and protection of UC blood cells during cryopreservation

BACKGROUND

Current procedures for the cryopreservation of umbilical cord blood (UCB) progenitor cells, which are based on techniques used for BM, have had varying degrees of success (survival 9-118%). Improving the effectiveness of UCB cell therapies demands a more comprehensive understanding of freezing injury during cryopreservation.

METHODS

Leukocyte concentrates from UCB, with or without 10% DMSO were cooled at 1 degrees C/min to different subzero temperatures (-5 to -50 degrees C), then either thawed directly (thaw) or plunged into liquid nitrogen before thawing (plunge). Single-platform flow cytometry with 7-amino-actinomycin D was used to directly quantify survival of CD34(+) cells. Fluorescent microscopy was used to examine plasma membrane integrity of nucleated cells.

RESULTS

Without DMSO, recovery of nucleated cells was approximately 80% for both thaw and plunge. Survival was 9%, indicating damage to the plasma membrane. With 10% DMSO, nucleated cell recovery was also approximately 80%, indicating that DMSO does not improve recovery of nucleated cells. Survival, however, was much higher with DMSO, > 60% for nucleated cells thawed directly, and 30-55% for cells thawed from plunge, demonstrating cryoprotection conferred by DMSO. With DMSO, survival of CD34(+) cells was higher than that of nucleated cells, indicating that CD34(+) cells with 10% DMSO are more tolerant to cryopreservation than the total nucleated cell population.

DISCUSSION

This study provides the necessary data on the low temperature response of UCB progenitor cells that are critical for the development of standards for the cryopreservation of UCB.

New genotypes in Fy(a-b-) individuals: nonsense mutations (Trp to stop) in the coding sequence of either FY A or FY B

Duffy blood group antigens are carried on a glycoprotein that is predicted to pass through the erythrocyte membrane seven times and is a promiscuous chemokine receptor. The Fy(a- b-) phenotype is present in two-thirds of African-American Blacks but is rare in Caucasians. In Blacks, the phenotype is due to a non-functional GATA-1 motif in the FY B, which silences the gene in erythrocytes but not in other tissues, and these patients do not generally make anti-Fyb or anti-Fy3. We describe here the molecular analysis of FY in three unrelated Caucasians who were studied because they had strong anti-Fy3 in their serum. Each was found to have a point mutation that was predicted to change a tryptophan to a premature stop codon in the coding sequence. In one patient (patient 1), the nonsense mutation was at nucleotide 287 of the major transcript in FY A; in another (patient 2), it was at nucleotide 407 in the major transcript of FY B; and in a third (patient 3), it was at nucleotide 408 of the major transcript of FY A.

Notifying patients exposed to blood products associated with Creutzfeldt-Jakob disease: integrating science, legal duties and ethical mandates

The issue of notifying people who have been exposed to blood products that have been associated with Creutzfeldt-Jakob disease (CJD) has arisen at a time when the Canadian blood system is under intense scrutiny. As a result, the Canadian Red Cross Society issued a recommendation to health care institutions that recipients of CJD-associated blood products be identified, notified and counselled. Although Canadian jurisprudence in the realm of informed consent may support a policy of individual notification, a review of the scientific evidence and the applicable ethical principles arguably favours a policy of a more general public notification. Indeed, situations such as this require a unique approach to the formation of legal and ethical duties, one that effectively integrates all relevant factors. As such, the authors argue that individual notification is currently not justified. Nevertheless, if a system of general notification is implemented (e.g., through a series of public health announcements), it should provide, for people who wish to know, the opportunity to find out whether they were given CJD-associated products.

Transfusion- and community-acquired cytomegalovirus infection in children with malignant disease: a prospective study

BACKGROUND

The use of cytomegalovirus (CMV)-"safe" blood has been recommended for CMV seronegative patients with newly diagnosed malignant disease for whom bone marrow transplantation is a future option.

STUDY DESIGN AND METHODS

To evaluate this policy, 76 CMV-seronegative children with lymphoreticular malignancies or solid tumors were randomly assigned to receive either blood components that were not screened for CMV antibody or CMV-seronegative red cell (RBC) and platelet units. Subjects were followed for evidence of CMV infection by the use of enzyme-linked immunosorbent assays and virus isolation. Follow-up continued long after the blood transfusions to determine the risk of community-acquired CMV infection.

RESULTS

No cases of transfusion-acquired CMV infection were documented. The prevalence of CMV IgG and IgM antibody in blood donors was 40.5 and 0.9 percent, respectively. Patients assigned to receive standard blood components and CMV-negative components were given a median (range) of 7 (1-30) and 9 (1-38) RBC units and 11 (0-123) and 14 (0-71) platelet units, respectively. The risk of transfusion-acquired CMV infection is estimated to be less than 1 in 698 donor exposures. Two patients developed asymptomatic community-acquired CMV infection, for an incidence of 1.7 percent per patient-year of follow-up.

CONCLUSION

The risk of transfusion-acquired CMV infection in this population is low, largely because of the patients' low level of exposure to seropositive blood and the use of relatively white cell-reduced components for purposes other than CMV prevention. Such children at this center therefore continue to receive standard blood components. Strategies to prevent CMV seroconversion in these children should include parental education to minimize the risk of community-acquired infection.

Benign retrorectal tumors in adults: the choice of operative approach

Six adult patients were treated for tumors of the retrorectal space from 1975 to 1990 at the University of Mississippi Medical Center. All were female; ages ranged from 19 to 64 (mean, 37.8) years. Two asymptomatic tumors were discovered in the peripartum period, and two patients had symptoms of local fullness or pain. One patient presented with a pelvic abscess, and one patient had had recurrent pilonidal cyst abscesses drained. All lesions were completely excised (one by a transsacral route, two by a transanal route, and three by a combined abdominosacral approach). All were histologically benign (four tailgut cysts and two epidermoid cysts). One tailgut cyst recurred after transanal excision and was removed by a transsacral route without further recurrence. Adequate excision may be achieved by any of several approaches. Transanal excision, although convenient for small low-lying dermoid tumors, resulted in the only recurrence in our series.

Benzopyranopyridine derivatives. 1. Aminoalkyl derivatives of the azaxanthenes as bronchodilating agents

The preparation of the four isomeric azaxanthones 3 and a number of their aromatic ring substituted derivatives is described. These ketones were converted into the title compounds which were examined for their biological properties. The most interesting compound in this series, the 1-methyl-4-piperidylidene derivative of 1-azaxanthene, shows the profile of an orally effective potent bronchodilating agent as well as a moderate antihistamine. Biological properties of this compound were compared to a number of antihistamines as well as known bronchodilating agents. Structure-activity relationships are also discussed.