Predictions of total work based on measures of muscle strength and hop performance in individuals after ACL reconstruction

OBJECTIVES

The purpose of this study was to determine the ability to utilize clinical measures of hop performance and thigh muscle strength to predict total limb work, a measure of cumulative single leg power, in young athletes at the time of return to sport after ACLR. We hypothesized that hop test performance and thigh muscle strength would predict total limb work during a maximal effort repeated vertical single-leg jump and that hop test performance would better predict total limb work during a maximal effort repeated vertical single-leg jump than measures of thigh strength.

DESIGN

Cross-sectional study.

PARTICIPANTS

Analysis on data from 50 individuals after unilateral ACLR (74% women, age 14-23 years) MAIN OUTCOME MEASURES: Performed 10-s repeated vertical single-leg jump test on a force platform where single limb power and resultant total work were calculated. At the same session, participants completed a clinical single leg hop test battery and thigh strength testing.

RESULTS

All clinical measures were associated with total work during the repeated vertical single-leg jump test on the involved and uninvolved limbs, respectfully. After controlling for height and weight, quadriceps femoris peak torque at 180°/s was the strongest predictor of total work for both limbs. On the involved limb, performance on the triple hop test for distance also uniquely contributed to the prediction of total work.

CONCLUSIONS

Quadriceps femoris muscle strength and distance hop test performance predict total limb work capacity of the involved limb during a single-leg dynamic task. Optimizing both measures after ACLR may positively impact vital components of sports performance.

A Review of Workload-Monitoring Considerations for Baseball Pitchers

Because of the unique demands of a pitch, baseball players have the greatest percentage of injuries resulting in surgery among high school athletes, with a majority of these injuries affecting the shoulder and elbow due to overuse from throwing. These injuries are believed to occur because of repeated microtrauma to soft tissues caused by the repetitive mechanical strain of throwing. Researchers and practitioners have suggested that baseball pitchers' workloads are a significant risk factor for injury in adolescent players, resulting in lost time and slowing of performance development. The purpose of our review was to investigate the current research relative to monitoring workload in baseball throwers and discuss techniques for managing and regulating cumulative stress on the arm, with a focus on preventing injury and optimizing performance in adolescent baseball pitchers.

In-home neurogaming: Demonstrating the impact of valid gesture recognition method on high volume kinematic outcomes

The process of cleaning motion capture data of aberrant points has been described as "the bane of motion capture operators". Yet, managing the high volume kinematic data generated through in-home neurogames requires data quality control that, executed insufficiently, jeopardizes accuracy of outcomes. To begin to address this issue at the intersection of biomechanics and "big data", we performed a secondary analysis of a neurogame, evaluating gesture count as well as shoulder and elbow joint angle outcomes calculated from kinematic data in which valid gestures were identified through 3 methods: visual review of regions of interest by an expert (BP); manufacturer-recommended data smoothing (MS); and automated methods (AI). We hypothesized that upper extremity kinematic outcomes from BP would be matched by AI but not MS methods. From one person with post-stroke hemiparesis, upper-extremity kinematic data were collected for 6 days over 2 weeks using a Microsoft Kinect™-based neurogame. We calculated gesture count, shoulder angle, and elbow angle outcomes from data managed using BP, MS, and AI methods. BP identified 1929 valid gestures total over 6 days which was different than the other two methods (p = 0.0015). In contrast, the AI algorithm with best precision identified 4372 and MS identified 4459 valid gestures. Furthermore, angle outcomes calculated from AI and MS methods resulted in different values than BP (p < 0.001 for 5 of 6 variables). More research is needed to automate treatment of high volume, low quality motion data to support investigation of motion associated with in-home rehabilitation neurogames.

The relationship between frontal plane trunk control during landing and lower extremity muscle strength in young athletes after anterior cruciate ligament reconstruction

BACKGROUND

Lower extremity landing asymmetries are common and associated with strength deficits after anterior cruciate ligament reconstruction. However, less is known regarding trunk control during landing. This study's hypotheses were that frontal plane trunk excursion during single-leg landing would be greater in young athletes after anterior cruciate ligament reconstruction compared to controls and would be associated with strength deficits.

METHODS

Participants included 130 young athletes recently cleared for return-to-sport following anterior cruciate ligament reconstruction and 56 uninjured young athletes. Frontal plane trunk excursion was quantified using three-dimensional motion analysis during a single-leg landing task. Quadriceps and hip abduction strength were measured using an isokinetic dynamometer. Frontal plane trunk excursion was compared between the anterior cruciate ligament reconstruction and control groups and among quadriceps strength subgroups using independent t-tests and one-way analysis of variance. Linear regression examined the association between frontal plane trunk excursion and strength measures in the anterior cruciate ligament reconstruction group.

FINDINGS

The anterior cruciate ligament reconstruction group demonstrated greater frontal plane trunk excursion compared to controls. The low-quadriceps group demonstrated greater frontal plane trunk excursion compared to both the high-quadriceps and control groups. Additionally, the high-quadriceps group demonstrated greater frontal plane trunk excursion compared to controls. In the anterior cruciate ligament reconstruction group, lower quadriceps and hip abduction strength were weakly associated with greater frontal plane trunk excursion.

INTERPRETATION

Young athletes at time of return-to-sport after anterior cruciate ligament reconstruction demonstrated increased frontal plane trunk excursion during single-leg landing. Additionally, increased frontal plane trunk excursion was weakly associated with strength deficits.

Changes in Throwing Arm Mechanics at Increased Throwing Distances During Structured Long-Toss

BACKGROUND

Elbow injuries among adolescent baseball players have been outpacing those of college and professional players. In attempts to prevent injuries and maximize return-to-play potential following injury, attention has been focused on "return to throw" programs, which include long-toss throws. Because the few studies that were conducted on long-toss throwing focused primarily on college-aged athletes, it is not known what type of load is incurred at the elbow during interval throwing progression among high school baseball players.

PURPOSE

To quantify the change in arm slot, arm speed, shoulder external rotation, and elbow varus torque across increasing throwing distances within a given athlete.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Ninety-five high school baseball players performed a long-toss protocol while wearing an inertial sensor and sleeve. Each participant was tested for 5 throws at distances of 9 m, 18 m, 27 m, 37 m, and 46 m. Linear mixed-effects models and likelihood ratio tests were used to estimate the within-participant relationship between throw distance and arm slot, arm speed, shoulder external rotation, and elbow varus torque.

RESULTS

Arm slot ( P < .01), arm speed ( P < .01), shoulder external rotation ( P < .01), and elbow varus torque ( P < .01) were significantly associated with long-toss throw distance. As the throw distance increased, there was an increase in arm speed and shoulder external rotation and a decrease in arm slot for each distance. However, elbow varus torque increased with each distance up to 37 m and then remained the same at 46 m.

CONCLUSION

The use of longer distances for conditioning and rehabilitation may be beneficial in increasing shoulder range of motion and arm speed; however, precaution needs to be taken, as throwing longer distances are accompanied by an increase in arm rotation, arm speed, and elbow torque, with a decrease in arm slot.

CLINICAL RELEVANCE

Return-to-throw programs have been utilized by sports medicine clinicians and coaches to help guide a player during rehabilitation. These programs involve throwing at increased efforts through increased distances with no immediate feedback on elbow stress. This investigation describes arm biomechanical changes during submaximum interval throwing and demonstrates a tool that can be utilized to measure arm stress in real time for clinicians and athletes progressing through an interval throwing program.

Assessing Risk and Related Complications after Reversal of Combat-Associated Ostomies

BACKGROUND

During the past decade of conflict, numerous patients with combat-associated injuries required the formation of an ostomy. However, outcomes in those patients undergoing ostomy reversal have yet to be analyzed. We review the experience and identify risk factors for complications after ostomy reversal in a series of patients with combat injuries at our military treatment facility.

STUDY DESIGN

A retrospective review of patients with combat-associated injuries managed with a diverting ostomy who underwent ostomy reversal at our military treatment facility during a 13-year period. Demographic and clinical data were collected for all patients and postoperative complications were identified. Multivariate analysis was performed to identify independent risk factors for complications after reversal. Complication rates were calculated for 90-day periods of time after ostomy creation and best-fit curve analysis was conducted.

RESULTS

Ninety-nine patients were identified who underwent ostomy reversal. Forty patients (40.4%) suffered a post-reversal complication. On multivariate analysis, older age (odds ratio 1.11/y; p = 0.038), severe perineal injury indication for diversion (odds ratio 4.37; p = 0.028), and increased time interval between ostomy creation and reversal (odds ratio 1.005/d; p = 0.037), were independently associated with postoperative complications. A cubic regression best fit quarterly complication rate data (R² 0.526; p < 0.001) and calculates a minimum complication rate for reversal 90 to 180 days after ostomy creation.

CONCLUSIONS

Ostomy reversal in patients wounded in combat is a major undertaking with a high complication rate. The finding of a shorter interval from ostomy creation to reversal independently associated with a reduction in complications provides a modifiable risk factor to guide future practice and potentially reduce complications. Our modeling suggests reversal in the 3- to 6-month time frame can have the lowest rate of complications. Future research to reduce complications is indicated, especially in older patients with perineal wounds.

Differential knee joint loading patterns during gait for individuals with tibiofemoral and patellofemoral articular cartilage defects in the knee

OBJECTIVE

To determine compartment-specific loading patterns during gait, quantified as joint reaction forces (JRF), of individuals with knee articular cartilage defects (ACD) compared to healthy controls (HC).

METHODS

Individuals with ACDs and HC participated. Individuals with ACDs were divided into groups according to ACD location: PF (only a patellofemoral ACD), TF (only a tibiofemoral ACD), and MIX (both PF and TF ACDs). Participants underwent three-dimensional gait analysis at self-selected speed. TF joint reaction force (TF-JRF) was calculated using inverse dynamics. PF joint reaction force (PF-JRF) was derived from estimated quadriceps force (F_QUAD) and knee flexion angle. Primary variables of interest were the PF- and TF-JRF peaks (body weight [×BW]). Related secondary variables (gait speed, quadriceps strength, knee function, activity level) were evaluated as covariates.

RESULTS

First peak PF-JRF and TF-JRF were similar in the TF and MIX groups (0.75-1.0 ×BW, P = 0.6-0.9). Both peaks were also similar in the PF and HC groups (1.1-1.3 ×BW, P = 0.7-0.8), and higher than the TF and MIX groups (P = 0.004-0.02). For the second peak PF-JRF, only the HC group was higher than the TF group (P = 0.02). The PF group walked at a similar speed as the HC group; both groups walked faster than the TF and MIX groups (P < 0.001). With gait speed and quadriceps strength as covariates, no differences were observed in JRF peaks.

CONCLUSIONS

The results suggest the presence of a TF ACD (TF and MIX groups), but not a PF ACD (PF group), may affect joint loading patterns during walking. Walking slower may be a protective gait modification to reduce load.

Relationships Between Standing Frontal-Plane Knee Alignment and Dynamic Knee Joint Loading During Walking and Jogging in Youth Who Are Obese

BACKGROUND

Youth who are obese have high risk of poor knee health and cartilage damage. Understanding factors which may affect knee health in youth who are obese is critical for preservation of knee integrity and function.

OBJECTIVE

This study compared standing frontal-plane knee alignment and knee loading patterns between youth who are obese and those of healthy weight and determine the association between knee alignment and knee loading patterns during walking and jogging.

DESIGN

This study used a cross-sectional matched pair design.

METHODS

Twenty youth who were obese and 20 youth who were healthy-weight (ages 11-18 years) were recruited. Three-dimensional motion analysis quantified standing frontal-plane knee alignment as well as frontal- and sagittal-plane knee moments during walking and jogging. Paired t -tests, multiple analysis of covariance, and Spearman's rank correlation coefficients were used for analysis.

RESULTS

The youth who were obese demonstrated greater knee valgus in standing ( P  = 0.02), lower normalized peak external knee adduction moments during walking ( P  = 0.003), and greater normalized peak external knee extension moments during jogging ( P  = 0.003) compared with the youth who were healthy-weight. Standing knee alignment did not correlate with knee moments in the youth who were obese.

LIMITATIONS

Results are limited to small, homogeneous cohorts. The standing alignment methodology is not validated in this population and may limit interpretation of results.

CONCLUSION

Youth who are obese stand in more knee valgus and have altered knee loading patterns during walking and jogging compared with youth who are healthy-weight. Frontal-plane knee alignment does not correlate with frontal-plane knee loading patterns in youth who are obese. A better understanding of other mechanisms related to joint loading in youth who are obese is necessary to maintain long-term joint integrity in this population.

Laparoscopy for Colon Cancer

The use of laparoscopy has become widespread across many surgical specialties. Its utility as treatment for colon cancer was initially met with hesitancy due to concern for port site and wound recurrences; however, this was later disproven by large retrospective series. Subsequently, there have been multiple, large, prospective, randomized studies evaluating laparoscopic versus open colectomy for colon cancer. All studies yielded similar results and showed no statistical difference in overall survival, disease-free survival, and recurrence. Additionally, these studies revealed similar operative outcomes with respect to complication rates, perioperative mortality, and conversion to open colectomy, as well as equivalent oncologic resections. Overall in the laparoscopic colectomy groups, hospital stays were shorter, and often times patients required less narcotics postoperatively, but laparoscopic operative times were longer. With adequate training, the use of laparoscopy can be safely employed for patients with colon cancer.

Hamstring Strength Asymmetry at 3 Years After Anterior Cruciate Ligament Reconstruction Alters Knee Mechanics During Gait and Jogging

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) using a hamstring tendon autograft often results in hamstring muscle strength asymmetry. However, the effect of hamstring muscle strength asymmetry on knee mechanics has not been reported.

HYPOTHESIS

Participants with hamstring strength asymmetry would demonstrate altered involved limb knee mechanics during walking and jogging compared with those with more symmetric hamstring strength at least 2 years after ACLR with a hamstring tendon autograft.

STUDY DESIGN

Controlled laboratory study.

METHODS

There were a total of 45 participants at least 2 years after ACLR (22 male, 23 female; mean time after ACLR, 34.6 months). A limb symmetry index (LSI) was calculated for isometric hamstring strength to subdivide the sample into symmetric hamstring (SH) (LSI ≥90%; n = 18) and asymmetric hamstring (AH) (LSI <85%; n = 18) groups. Involved knee kinematic and kinetic data were collected using 3-dimensional motion analysis during gait and jogging. Peak sagittal-, frontal-, and transverse-plane knee angles and sagittal-plane knee moments and knee powers were calculated. Independent-samples t tests and analyses of covariance were used to compare involved knee kinematic and kinetic variables between the groups.

RESULTS

There were no differences in sagittal- and frontal-plane knee angles between the groups ( P > .05 for all). The AH group demonstrated decreased tibial internal rotation during weight acceptance during gait ( P = .01) and increased tibial external rotation during jogging at initial contact ( P = .03) and during weight acceptance ( P = .02) compared with the SH group. In addition, the AH group demonstrated decreased peak negative knee power during midstance ( P = .01) during gait compared with the SH group, after controlling for gait speed, which differed between groups.

CONCLUSION

Participants with hamstring strength asymmetry showed altered involved knee mechanics in the sagittal plane during gait and in the transverse plane during gait and jogging compared with those with more symmetric hamstring strength.

CLINICAL RELEVANCE

Hamstring strength asymmetry is common at 3 years after ACLR with a hamstring tendon autograft and affects involved knee mechanics during gait and jogging. Additional research is warranted to further investigate the longitudinal effect of these alterations on knee function and joint health after ACLR.

Portable Myoelectric Brace Use Increases Upper Extremity Recovery and Participation But Does Not Impact Kinematics in Chronic, Poststroke Hemiparesis

The authors examined the efficacy of an 8-week regimen combining repetitive task-specific practice (RTP) with a myoelectric brace (RTP+Myomo) on paretic upper extremity (UE; use in valued activities, perceived recovery, and reaching kinematics) in 12 subjects (4 men; M age = 53.5 years; mean time poststroke = 61.7 months). Seven subjects were administered RTP+Myomo therapy, and 5 were administered RTP only. Both groups participated in individualized, 45-min therapy sessions occurring 3 days/week over an 8-week period. The arm, hand ability, activities of daily living, and perceptions of recovery subscales of the Stroke Impact Scale (SIS), as well as UE reaching kinematics, assessed before and after the intervention. Subjects in the RTP+Myomo group showed greater improvements on all SIS subscales, with the recovery scale reaching statistical significance (p = .03). Subjects in the RTP-only group showed a greater increase in hand velocity in the reach up task (p = .02), but no changes were observed in the range of shoulder flexion or elbow extension during reaching. None of the changes in kinematic outcome measures significantly correlated with any of the changes in SIS subscales. RTP integrating myoelectric bracing may be more beneficial than RTP only in improving self-reported function and perceptions of overall recovery. The authors observed no changes in the range of elbow extension, and no relationship between self-reported improvements and changes in reaching kinematics.

Validation of a method to accurately correct anterior superior iliac spine marker occlusion

Anterior superior iliac spine (ASIS) marker occlusion commonly occurs during three-dimensional (3-D) motion capture of dynamic tasks with deep hip flexion. The purpose of this study was to validate a universal technique to correct ASIS occlusion. 420 ms of bilateral ASIS marker occlusion was simulated in fourteen drop vertical jump (DVJ) trials (n=14). Kinematic and kinetic hip data calculated for pelvic segments based on iliac crest (IC) marker and virtual ASIS (produced by our algorithm and a commercial virtual join) trajectories were compared to true ASIS marker tracking data. Root mean squared errors (RMSEs; mean±standard deviation) and intra-class correlations (ICCs) between pelvic tracking based on virtual ASIS trajectories filled by our algorithm and true ASIS position were 2.3±0.9° (ICC=0.982) flexion/extension, 0.8±0.2° (ICC=0.954) abduction/adduction for hip angles, and 0.40±0.17 N m (ICC=1.000) and 1.05±0.36 N m (ICC=0.998) for sagittal and frontal plane moments. RMSEs for IC pelvic tracking were 6.9±1.8° (ICC=0.888) flexion/extension, 0.8±0.3° (ICC=0.949) abduction/adduction for hip angles, and 0.31±0.13 N m (ICC=1.00) and 1.48±0.69 N m (ICC=0.996) for sagittal and frontal plane moments. Finally, the commercially-available virtual join demonstrated RMSEs of 4.4±1.5° (ICC=0.945) flexion/extension, 0.7±0.2° (ICC=0.972) abduction/adduction for hip angles, and 0.97±0.62 N m (ICC=1.000) and 1.49±0.67 N m (ICC=0.996) for sagittal and frontal plane moments. The presented algorithm exceeded the a priori ICC cutoff of 0.95 for excellent validity and is an acceptable tracking alternative. While ICCs for the commercially available virtual join did not exhibit excellent correlation, good validity was observed for all kinematics and kinetics. IC marker pelvic tracking is not a valid alternative.

Controversies surrounding quality measurement in colon and rectal surgery

Quality improvement in health care has become a major topic of discussion among health care providers, patients, insurance companies, and the government. National Surgical Quality Improvement Project (NSQIP), along with a multitude of other programs, exists in an attempt to create objective data that can be used to compare hospitals and providers against a national average. Studies have shown that despite good patient care and proper surgical technique, patients who undergo procedures such as colectomy have a higher incidence of surgical site infection (SSI) and other morbidities. Therefore, hospitals with a large volume of colon and rectal surgery cases are routinely identified as "high outliers" in these quality improvement programs. Programs, such as NSQIP, may not be the best way to measure quality in specific subspecialties such as colon and rectal surgery.

Hip adductor activations during run-to-cut manoeuvres in compression shorts: implications for return to sport after groin injury

Athletes at high risk of groin strains in sports such as hockey and soccer often choose to wear shorts with directional compression to aid in prevention of or recovery from hip adductor strains. Large, eccentric contractions are known to result in or exacerbate strain injuries, but it is unknown if these shorts have a beneficial effect on hip adductor muscle activity. In this study, surface electromyography (EMG) of the adductor longus and ground reaction force (GRF) data were obtained simultaneously on 29 healthy individuals without previous history of serious injury while performing unanticipated 45° run-to-cut manoeuvres in a laboratory setting wearing shorts with non-directional compression (control, HeatGear, Under Armour, USA) or shorts with directional compression (directional, CoreShort PRO, Under Armour, USA), in random order. Average adductor activity in the stance leg was significantly lower in the directional condition than in the control condition during all parts of stance phase (all P < 0.042). From this preliminary analysis, wearing directional compression shorts appears to be associated with reduced stance limb hip adductor activity. Athletes seeking to reduce demand on the hip adductors as they approach full return to activities may benefit from the use of directional compression shorts.

Lower extremity work is associated with club head velocity during the golf swing in experienced golfers

While the golf swing is a complex whole body movement requiring coordination of all joints to achieve maximum ball velocity, the kinetic contribution of the lower extremities to club head velocity has not been quantified, despite the perception that the legs are a primary source of power during the swing. Mechanical power at the hips, knees, and ankles was estimated during the downswing phase of a full swing with a driver using a passive optical motion capture system and 2 force plates for adult males across a range of age and self-reported skill levels. Total work by the lower extremities was calculated by integrating the powers of all 6 joints over the downswing. Regression analyses showed that total lower extremity work was a strong predictor of club head velocity (R=0.63). Secondary analyses showed different relationships to club head velocity in lead and trail leg lower extremity joints, but none of these were as predictive of club head velocity as the total work performed by the lower extremities. These results provide quantitative evidence that the lower body's kinetic contribution may be an important factor in achieving greater club head velocity, contributing to greater driving distance and overall golf performance.

Ipsilateral motor cortical responses to TMS during lengthening and shortening of the contralateral wrist flexors

Unilateral lengthening contractions provide a greater stimulus for neuromuscular adaptation than shortening contractions in the active and non-active contralateral homologous muscle, although little is known of the potential mechanism. Here we examined the possibility that corticospinal and spinal excitability vary in a contraction-specific manner in the relaxed right flexor carpi radialis (FCR) when humans perform unilateral lengthening and shortening contractions of the left wrist flexors at the same absolute force. Corticospinal excitability in the relaxed right FCR increased more during lengthening than shortening at 80% and 100% of maximum voluntary contraction (MVC). Short-interval intracortical inhibition diminished during shortening contractions, and it became nearly abolished during lengthening. Intracortical facilitation lessened during shortening but increased during lengthening. Interhemispheric inhibition to the 'non-active' motor cortex diminished during shortening, and became nearly abolished during lengthening at 90% MVC. The amplitude of the Hoffman reflex in the relaxed right FCR decreased during and remained depressed for 20 s after lengthening and shortening of the left wrist flexors. We discuss the possibility that instead of the increased afferent input, differences in the descending motor command and activation of brain areas that link function of the motor cortices during muscle lengthening vs. shortening may cause the contraction-specific modulation of ipsilateral motor cortical output. In conclusion, ipsilateral motor cortex responses to transcranial magnetic stimulation are contraction-specific; unilateral lengthening and shortening contractions reduced contralateral spinal excitability, but uniquely modulated ipsilateral corticospinal excitability and the networks involved in intracortical and interhemispheric connections, which may have clinical implications.

Venous thromboembolic disease in colorectal patients

Venous thromboembolic disease, which includes deep vein thromboses as well as pulmonary emboli, can be a significant complication in the postoperative patient. In particular, colorectal patients often carry a higher risk for venous thromboembolism when compared with patients undergoing other operative procedures. Features unique to colorectal patients are the high incidence of inflammatory bowel disease or malignancy. Typically, these patients will undergo lengthy pelvic procedures, which also contribute to a cumulative risk of venous thrombosis. It is critical that all patients and the proposed operative procedure are appropriately risk stratified. Risk stratification allows for easier implementation of an appropriate prophylactic strategy. There are a wide range of safe and effective mechanical and pharmacologic measures available. The authors provide very specific recommendations, but note that clinical judgment plays a significant role.

Endocavitary contact radiation therapy for ultrasonographically staged T1 N0 and T2 N0 rectal cancer

Background

The purpose of this study was to determine the long-term outcomes of patients undergoing endocavitary contact radiation therapy (ECR) for stage I rectal cancer.

Methods

A database of patients treated with ECR for biopsy-proven rectal adenocarcinoma from July 1986 to June 2006 was reviewed retrospectively. Only patients with primary, non-metastatic, ultrasonographically staged T1 N0 and T2 N0 cancer who had no adjuvant treatment were included. Patients received a median of 90 (range 60–190) Gy contact radiation, delivered transanally by a 50-kV X-ray tube in two to five fractions.

Results

Of 149 patients, 77 (40 T1, 37 T2) met the inclusion criteria. Median age was 74 (range 38–104) years, and median follow-up 69 (range 10–219) months. ECR failed in 21 patients (27 per cent) (persistent disease, four; recurrence, 17), of whom ten remained disease free after salvage therapy. The estimated 5-year disease-free survival rate was 74 (95 per cent confidence interval 63 to 83) per cent after ECR alone, and 87 (76 to 93) per cent when survival after salvage therapy for recurrence was included.

Conclusion

ECR is a minimally invasive treatment option for early-stage rectal cancer. However, similar to other local therapies, ECR has a worse oncological outcome than radical surgery.

Benign pneumoperitoneum after colonoscopy: a prospective pilot study

Benign pneumoperitoneum is asymptomatic free intraabdominal air and is reported to occur occasionally with colonoscopy. Management of benign pneumoperitoneum after colonoscopy is controversial and may depend on incidence or etiology. No previous studies prospectively investigated the incidence or inciting factors of benign pneumoperitoneum resulting from colonoscopy. In this study, 100 patients underwent colonoscopy and then radiography of the chest and abdomen to detect free air. The average age was 58 +/- 6.2 years, and 48 of the colonoscopies were therapeutic. No cases of benign pneumoperitoneum were detected, estimating the incidence at 0% to 3% for diagnostic and therapeutic colonoscopy. These data indicate that benign pneumoperitoneum attributable to colonoscopy is rare and possibly nonexistent. Given the paucity of data favoring the occurrence of benign pneumoperitoneum after colonoscopy, we advocate treating all cases of free intraabdominal air after colonoscopy as perforations.

Femoral vessel injuries in modern warfare since Vietnam

The incidence of lower extremity injuries is high in modern warfare; however the mortality rate from these injuries is low. Despite the overall low mortality of lower extremity injuries, many deaths in modern conflicts are due to femoral vessel injury. The modern warfare literature was reviewed. In Somalia, 1 of the 14 reported deaths was due to a laceration of the superficial femoral artery. In the Persian Gulf, three deaths were reported in an Army field hospital, one resulted from uncontrolled hemorrhage from a profunda femoris artery wound and two others resulted from traumatic amputations with consequent major arterial injury. Despite the advances in modern body armor, the groin is left unprotected. A strategy to help minimize U.S. casualties in modern warfare may be a method of field hemostasis specifically designed for femoral vessel injury.

Selective IgA deficiency in Australian blood donors

Selective serum IgA deficiency (defined as a serum IgA level less than 50 mg/l) was detected in 14 of 6,191 Australian blood donors screened by double diffusion analysis of serum specimens in agarose. This prevalence rate of 0.23% (1 in 442) is the same as that found in blood donors in Sweden but is higher than rates found in blood donors in France (0.05%), Norway (0.08%), USA (0.15%). England (0.19%) and Finland (0.20%). Antibodies to human IgA were detected in the serum of three of 11 blood donors with selective IgA deficiency (27%). There was no evidence in the present study of blood transfusion reactions from these anti-IgA antibodies when they were transfused into recipients.

Paraproteinaemia in inbred chickens

Sera from seventy chickens of several inbred lines were screened by cellulose acetate electrophoresis for abnormalities of immunoglobulin production. IgG levels in two sera (both from apparently healthy birds) were unusually high. The IgG proteins purified from these two sera were shown, by isoelectric focusing, to be of restricted heterogeneity.