Effect of wheelchair configurations on shoulder movements, push rim kinetics and upper limb kinematics while negotiating a speed bump.

This study aimed to provide a comprehensive assessment of upper limb kinetics and kinematics and shoulder movements during wheelchair propulsion while negotiating a speed bump of 6 cm height using four different wheelchair configurations. 16 healthy males aged 30.8 ± 5.7 years participated in the experiment. The kinetic and kinematic data during wheelchair propulsion were recorded. A smart system was used to collect the push forces and a motion capture system was used to collect upper limb movements. The results show that approximately 50% more pushing force was required to negotiate the speed bump than that of level ground propulsion. At the upward-forward axle position, peak total forces were 95.17 ± 5.70 N which resulted in significantly improved propulsion ergonomics, but 129.36 ± 6.68 N was required at the upward-back axle position at the speed bump push. The findings could help manufactures to design protective gloves for wheelchair users and provide useful rehabilitation information to clinicians and patients. Practitioner summary: This study investigated pushing forces and movements during wheelchair propulsion over a speed bump. Approximately 50% more pushing force was required to negotiate the bump than a level surface propulsion. The upper-forward axle position was found to be reasonably better than other positions during wheelchair propulsion. Abbreviations: UF: upper and forward position; UB: upper and back position; DF: down and forward position; DB: down and back position; ROM: range of motion.

Volar plating: functional recovery of the pronator quadratus.

PURPOSE: The pronator quadratus (PQ) is reflected in the surgical approach to the distal radius. This study explores the functional strength of PQ, 12 months after volar plating without repair of PQ. METHODS: A total of 135 patients were identified from our prospectively collected database. All volunteers had grip strength and pronation power tested in the treated and contralateral forearms at 45, 90 and 135 degrees of elbow flexion using a custom-built torque measuring device and hydraulic hand dynamometer to evaluate forearm pronation. RESULTS: Twenty-seven participants were included in the study. No significant difference was identified in mean peak pronation torque between the volar plated and non-treated forearms. Pronation strength was identified as being independent of angle of elbow flexion. Grip strength was correlated with forearm pronation showing no significant difference between groups. CONCLUSIONS: Our results suggest adequate long-term (15-32 months) functional recovery of the pronator quadratus after volar plating. LEVEL OF EVIDENCE: III.

Development of a Microscopic Colitis Disease Activity Index: a prospective cohort study.

OBJECTIVE: Microscopic colitis (MC) is a common cause of chronic diarrhoea, often with additional symptoms. No validated instruments exist to assess disease activity in MC, making it difficult to compare efficacy of treatments between clinical trials. We aimed to identify clinical features that independently predicted disease severity and create a Microscopic Colitis Disease Activity Index (MCDAI). DESIGN: Patients with MC were prospectively administered a survey assessing their GI symptoms and the IBD Questionnaire (IBDQ). A single investigator also scored a physician global assessment (PGA) of disease severity on a 10-point scale. Multiple linear regression identified which symptoms best predicted the PGA. These symptoms were then combined in a weighted formula to create the MCDAI. The relationship between MCDAI and the IBDQ was investigated. RESULTS: Of the 175 patients enrolled, 13 (7.4%) did not complete the survey. The remaining 162 had a median age of 66 years (range, 57-73) and 74% were female. Several clinical features were independently associated with PGA (number of unformed stools daily, presence of nocturnal stools, abdominal pain, weight loss, faecal urgency and faecal incontinence). These parameters were combined to create the MCDAI, which strongly predicted the PGA (R2=0.80). A 1-unit decrease in disease activity (ΔMCDAI) was associated with a 9-unit increase in quality of life (ΔIBDQ). CONCLUSIONS: The MCDAI strongly predicted the PGA and correlated with a validated measure of quality of life. Several symptoms in addition to diarrhoea are associated with disease severity in MC.

The effect of perindopril on postural instability in older people with a history of falls-a randomised controlled trial.

Design: double-blind, parallel group, placebo-controlled randomised trial. Methods: we recruited people aged >65 years with at least one fall in the previous year. Participants received 4 mg perindopril or placebo daily for 15 weeks. The primary outcome was the between-group difference in force-plate measured anteroposterior (AP) sway at 15 weeks. Secondary outcomes included other measures of postural sway, limits of stability during maximal forward, right and left leaning, blood pressure, muscle strength, 6-min walk distance and falls. The primary outcome was assessed using two-way ANOVA, adjusted for baseline factors. Results: we randomised 80 participants. Mean age was 78.0 (SD 7.4) years; 60 (75%) were female. About 77/80 (96%) completed the trial. At 15 weeks there were no significant between-group differences in AP sway with eyes open (mean difference 0 mm, 95% CI -8 to 7 mm, P = 0.91) or eyes closed (mean difference 2 mm, 95% CI -7 to 12 mm, P = 0.59); no differences in other measures of postural stability, muscle strength or function. About 16/40 (42%) of patients in each group had orthostatic hypotension at follow-up. The median number (IQR) of falls was 1 (0,4) in the perindopril versus 1 (0,2) in the placebo group (P = 0.24). Conclusions: perindopril did not improve postural sway in older people at risk of falls. Clinical Trials Registration: ISRCTN58995463.

Comparison of revision risks and complication rates between total HIP replacement and HIP resurfacing within the similar age group.

BACKGROUND AND PURPOSE: Currently it is not clear whether age is a factor affecting revisions in total hip replacement (THR) and hip resurfacing (HR). This study aimed to investigate which of THR or HR has a higher risk in terms of revision and complication within similar age groups. METHODS: A systemic review was performed for published literature research databases and local data and compared the two procedures under the condition that both groups of patients were age matched. Meta-analysis techniques were used to analyse revision and complication rates. Twenty-seven literature studies were included along with local audit data. In total, 2520 HR procedures were compared with age-matched 2526 of THR procedures. MAIN FINDINGS: It was found that revision risk of HR is significantly higher than THR (risk ratio 1.65, 95% CI 1.28-2.31, p < 0.0001), highlighting that HR has a slightly higher chance of reoperation when compared to THR within the similar age group population. In terms of complications, HR was found to have an advantage over THR (risk ratio 0.84, 95% CI 0.73-0.96, p < 0.01). CONCLUSION: THR had a lower revision risk but a slightly higher complication risk than HR under the condition that the two surgical procedures were applied to similar age groups of patients. In other words, age has not played an important role in revision and complication. Survivorship cannot be measured as follow-up periods were different in the studies used.

Kinematical analysis of the trunk, upper limbs and fingers during minimal access surgery when using an armrest.

This study investigated whether using an armrest could reduce the movements of the trunk, upper limb and hand of surgeons during simulated minimal access surgery. Sixteen surgeons carried out two trials of simulated laparoscopic surgery, one using an armrest and the other without. Reflective markers were attached on the trunk, upper limbs, fingers, minimal access camera (MAC) and scissors, allowing a motion capture system to record the movements. The error ratios during operation, subjective opinions and operative durations were collected. The results showed that total displacements at the trunk and shoulders were reduced by at least 25% when using an armrest compared with not using one; error ratios were reduced by 7%; velocity and acceleration in the trunk, shoulder and MAC were reduced. After simulated operations, 78% of the participants preferred using the armrest. The study indicates that an armrest could improve surgical outcomes by reducing trunk movements. PRACTITIONER SUMMARY: An armrest may help surgeons to reduce unnecessary movements during operations. The error ratios were reduced by 7% when using an armrest compared with no armrest. Displacements at the trunk and shoulders were reduced by 25% when using an armrest. Seventy-eight per cent of participants preferred to use an armrest after the experiment.

GAIT PATTERN RECOGNITION IN CEREBRAL PALSY PATIENTS USING NEURAL NETWORK MODELLING.

BACKGROUND: Interpretation of gait data obtained from modern 3D gait analysis is a challenging and time consuming task. The aim of this study was to create neural network models which can recognise the gait patterns from pre- and post-treatment and the normal ones. Neural network is a method which works on the principle of learning from experience and then uses the obtained knowledge to predict the unknowns. METHODS: Twenty-eight patients with cerebral palsy were recruited as subjects whose gait was analysed in pre and post-treatment. A group of twenty-six normal subjects also participated in this study as control group. All subjects' gait was analysed using Vicon Nexus to obtain the gait parameters and kinetic and kinematic parameters of hip, knee and ankle joints in three planes of both limbs. The gait data was used as input to create neural network models. A total of approximately 300 trials were split into 70% and 30% to train and test the models, respectively. Different models were built using different parameters. The gait modes were categorised as three patterns, i.e., normal, pre- and post-treatments. RESULTS: The results showed that the models using all parameters or using the joint angles and moments could predict the gait patterns with approximately 95% accuracy. Some of the models e.g., the models using joint power and moments, had lower rate in recognition of gait patterns with approximately 70-90% successful ratio. CONCLUSION: Neural network models can be used in clinical practice to recognise the gait pattern for cerebral palsy patients.

Analysis of joint force and torque for the human and non-human ape foot during bipedal walking with implications for the evolution of the foot.

The feet of apes have a different morphology from those of humans. Until now, it has merely been assumed that the morphology seen in humans must be adaptive for habitual bipedal walking, as the habitual use of bipedal walking is generally regarded as one of the most clear-cut differences between humans and apes. This study asks simply whether human skeletal proportions do actually enhance foot performance during human-like bipedalism, by examining the influence of foot proportions on force, torque and work in the foot joints during simulated bipedal walking. Skeletons of the common chimpanzee, orangutan, gorilla and human were represented by multi-rigid-body models, where the components of the foot make external contact via finite element surfaces. The models were driven by identical joint motion functions collected from experiments on human walking. Simulated contact forces between the ground and the foot were found to be reasonably comparable with measurements made during human walking using pressure- and force-platforms. Joint force, torque and work in the foot were then predicted. Within the limitations of our model, the results show that during simulated human-like bipedal walking, (1) the human and non-human ape (NHA) feet carry similar joint forces, although the distributions of the forces differ; (2) the NHA foot incurs larger joint torques than does the human foot, although the human foot has higher values in the first tarso-metatarsal and metatarso-phalangeal joints, whereas the NHA foot incurs higher values in the lateral digits; and (3) total work in the metatarso-phalangeal joints is lower in the human foot than in the NHA foot. The results indicate that human foot proportions are indeed well suited to performance in normal human walking.

Energy consumption during simulated minimal access surgery with and without using an armrest.

BACKGROUND: Minimal access surgery (MAS) can be a lengthy procedure when compared to open surgery and therefore surgeon fatigue becomes an important issue and surgeons may expose themselves to chronic injuries and making errors. There have been few studies on this topic and they have used only questionnaires and electromyography rather than direct measurement of energy expenditure (EE). The aim of this study was to investigate whether the use of an armrest could reduce the EE of surgeons during MAS. METHOD: Sixteen surgeons performed simulated MAS with and without using an armrest. They were required to perform the time-consuming task of using scissors to cut a rubber glove through its top layer in a triangular fashion with the help of a laparoscopic camera. Energy consumptions were measured using the Oxycon Mobile system during all the procedures. Error rate and duration time for simulated surgery were recorded. After performing the simulated surgery, subjects scored how comfortable they felt using the armrest. RESULTS: It was found that O(2) uptake (VO(2)) was 5 % less when surgeons used the armrest. The error rate when performing the procedure with the armrest was 35 % compared with 42.29 % without the armrest. Additionally, comfort levels with the armrest were higher than without the armrest. 75 % of surgeons indicated a preference for using the armrest during the simulated surgery. CONCLUSION: The armrest provides support for surgeons and cuts energy consumption during simulated MAS.

Mechanisms of cervical spine injury in rugby union: a systematic review of the literature.

BACKGROUND: Severe cervical spine injury in rugby union (rugby) exerts a major impact on the individual who sustains the injury and on the broader society. Since the late 1970s, authors of rugby case report studies have postulated that the underlying mechanism of cervical spine injury is hyperflexion of the neck. However, this is in conflict with findings from more recent experimental studies. These have shown that it is more likely that the majority of cervical spine injuries occur due to buckling of the cervical spinal column. OBJECTIVE: To investigate the primary mechanism of cervical spine injury in rugby. METHODS: A comprehensive and systematic review of the literature was undertaken. Six key factors were identified and subsequently used to investigate the two principally postulated mechanisms of cervical spine injury: hyperflexion and buckling. RESULTS: Facet dislocations, in particular bilateral facet dislocations, were identified as the most common types of cervical spine injury in rugby. Trauma occurred most often at lower cervical spinal levels, notably the C4/5 and C5/6 motion segments. Experimental studies demonstrate that bilateral facet dislocations occurring at the lower cervical spinal levels are primarily produced via buckling. CONCLUSION: Our analysis of key factors for cervical spine injury in rugby shows that it is unlikely that the majority of injuries occur after hyperflexion of the neck. It appears more likely that they are the result of buckling of the cervical spinal column.

Comparison of two actuation systems for laparoscopic surgical manipulators using motion analysis.

BACKGROUND: During surgery, all joints of the upper limbs, including shoulder, elbow, wrist, and finger, coordinate to complete a task. Hence, analysis of these joint movements during surgical manipulations is useful for the design of optimal hand-instrument interface. This study compared two types of surgical handheld manipulators with 6 degrees of freedom with different handle designs: one using a controlling wheel (fingertip control, FTC) and the other with a controlling joint (master slave control, MSC) in terms of ergonomics and movement efficiency. METHODS: Seventeen subjects consisting of surgeons and medical students participated in the experiment. Each performed two standardized surgical tasks in a surgical simulator. A set of reflective markers were attached on the subjects' upper limbs and the marker positions during the tasks were collected by a motion capture system for subsequent analysis of the trunk, shoulder, elbow, wrist, and fingers joint movements. The subjects also completed a Visual Analogue Scale-based questionnaire on their preference for the control mechanism and ease of handling. RESULTS: The data showed that the manipulator with the MSC was more difficult to handle and resulted in larger range of movements, higher velocities, and accelerations in some joints than the manipulator with FTC mechanism. Use of the MSC manipulator also was accompanied by a higher error rate. Additionally, the subjects preferred the finger actuated manipulator and gave it a higher Visual Analogue Score for maneuverability. CONCLUSIONS: The manipulator equipped with the MSC was ergonomically inferior; it was more difficult to handle and provided less precision, resulting in higher error rates than the FTC manipulator. This study also confirmed that motion analysis is useful for assessment of the design of handheld manipulators for endoscopic surgery.

Does the Oxford Knee Score complement, concur, or contradict the American Knee Society Score?

The American Knee Society Score (AKSS) and the Oxford Knee Score (OKS) are commonly used outcome assessment tools following total knee arthroplasty. The literature is sparse with regard to direct correlation between the AKSS and the OKS. The present study aimed to elucidate any direct correlation between these two scoring systems. Preoperative and 1-year postoperative AKSS and OKS from 379 patients were analyzed statistically. Regression equations were developed based on curve fit models. The study found a good correlation between the two scoring systems. The OKS can be used as a screening tool to identify which patients need to be assessed clinically in the short term (<2 years) following total knee arthroplasty (TKA). This will have significant cost-benefit implications. It is also possible to predict the AKSS from OKS using mathematical equations developed for this study. This method of predicting the AKSS from the OKS has not previously been described.

Forecasting Posttreatment Outcome of Hallux Valgus Surgery Patients.

BACKGROUND: Despite advancements in operative techniques and the extraordinary number of procedures described for correcting hallux valgus (HV), there is still uncertainty as to why some patients thrive postoperatively whereas others do not. This study aimed to investigate whether the postoperative outcome of HV surgery could be predicted from patient demographics or functional impairment at the time of referral. METHODS: The prospectively collected data, from 92 patients, were analyzed to determine whether patient demographics significantly influenced outcome 52 weeks after surgery. Potential relationships between socioeconomic deprivation and the outcome, as well as between preoperative functional impairment and postoperative improvement, were examined. The Manchester Oxford Foot Questionnaire (MOXFQ) and Scottish Index of Multiple Deprivation (SIMD) were used in this evaluation. RESULTS: None of the demographics studied were found to be statistically significant determinants of outcome. Preoperative MOXFQ scores for patients from the most deprived areas were significantly worse at the time of referral. Patients living in the least deprived postcodes experienced the lowest improvement in MOXFQ scores. Patients from the most deprived SIMD quintile achieved significantly higher improvement in MOXFQ-walking and standing compared to those from the least deprived quintile. A strong positive correlation was found between the preoperative MOXFQ scores and the improvement in the scores postoperatively. CONCLUSION: In this patient cohort, demographics could not be used to predict the postoperative outcome at week 52. Socioeconomic disparities seem to influence the timing of patients seeking surgery. Lower preoperative MOXFQ scores strongly correlate with a lesser degree of postoperative improvement. LEVEL OF EVIDENCE: Level III, retrospective study with prospective arm.

Kinematic 3-D motion analysis of shoulder resurfacing hemiarthroplasty - An objective assessment method.

Shoulder replacement is indicated in the treatment of pain due to osteoarthritis. Few studies have objectively assessed range of motion (RoM) gains at different post-operative time points. This is a prospective 3D motion analysis study to objectively quantify RoM changes at multiple time points following shoulder resurfacing arthroplasty (SRA) for primary gleno-humeral osteoarthritis, comparing it with clinically measured RoM. Clinical assessment, Visual Analog Scale (VAS) pain score, Constant-Morley (CS) and Oxford Shoulder Score (OSS) were recorded. Motion analysis was performed for RoM and three activities of daily living tasks (ADL), pre-operatively and post-operatively at 4 and 12 months. Nineteen shoulders in fifteen patients were included. The mean age was 72 years (range 52-84). There were significant improvements in external and internal rotation, ability to place the hand behind the head and reach the fifth lumbar vertebra, at 4 months on clinical examination and kinematic analysis with no further improvements at 12 months. There was significant improvement in abduction at 4 months with further improvement at 12 months, which was significantly more than noted on clinical assessment. In contrast, kinematic analysis showed a reduction in flexion between 4 and 12 months, while clinically there appeared to be an improvement between these time periods. This is the first study to prospectively utilise objective kinematic 3-D motion analysis in addition to clinical measurements and outcome scores, to investigate the outcome of resurfacing arthroplasty at multiple time points after surgery, providing an understanding into the trends of change in these parameters.

The impact of advances in instrumentation and techniques of colonoscopy from 1988 to 2008 on inpatient colonoscopy performance at a high volume endoscopy unit in the United States: significantly shorter procedure time, higher completion rate, performance on sicker inpatients, and near disappearance of flexible sigmoidoscopy.

BACKGROUND AND AIMS: Colonoscopy instrumentation and technique have improved from 1988 to 2008. We analyze whether these improvements have resulted in improved colonoscopy performance. METHODS: This was a retrospective study of 50 consecutive inpatients in 1988 vs. 1998 vs. 2008 undergoing intended colonoscopy at a teaching hospital. Patient APACHE score, cecal and terminal ileal intubation rates, procedure time, and colonoscopic diagnoses were compared for the three different years. RESULTS: Changes in practice of inpatient colonoscopy in 2008 from 1988 include (1) remarkably sicker inpatients undergoing colonoscopy in 2008, as indicated by: significantly higher mean APACHE II score (11.0 ± 6.6 vs. 5.9 ± 4.1, P < 0.00001), significantly more frequent monitored bed status (58% vs. 10%, OR = 12.4; 95%-ORCI: 4.31-35.4, P < 0.00001), and significantly higher rates of several chronic diseases (e.g. CHF, 24% vs. 6%, P = 0.02); (2) significantly higher colonoscopy completion rate in 2008 (88% vs. 64%; OR = 4.13, 95%-ORCI: 1.51-11.2, P = 0.009); (3) significantly higher terminal ileum intubation rate in 2008 (44% vs. 14%, OR = 4.83, 95%-ORCI: 1.85-12.5, P = 0.002); and (4) significantly shorter mean procedure time in 2008 (26.3 ± 7.9 min vs. 48.0 ± 20.3 min, P < 0.00001). The ratio of intended colonoscopy/flexible sigmoidoscopy was significantly higher in 2008 vs. 1988 (OR = 7.50, 95%-ORCI: 2.56-21.8, P < 0.00001). Internal hemorrhoids were significantly more frequently diagnosed by colonoscopy in 2008 (44% vs. 12%, OR = 5.76, 95%-ORCI: 2.12-15.5, P = 0.001), attributed to increased rectal retroflexion. CONCLUSIONS: Due to improved instrumentation and technique, colonoscopy has dramatically changed from 1988 to become a clinically more valuable test in 2008 as manifested by a higher completion rate, greater clinical applicability, and shorter procedure time. Colonoscopy is supplanting flexible sigmoidoscopy.

Impairment of maturation of BMP-6 (35 kDa) correlates with delayed fracture healing in experimental diabetes.

BACKGROUND: Although it is known that diabetes interferes with fracture healing, the mechanisms remain poorly understood. The aim of this study was to investigate the correlation of BMP-6 and BMP-9 with the impairment in fracture healing in diabetes, by analyses of the difference in size and calcification of the callus, mechanical endurance, and expressing BMP-6 and BMP-9 in the callus, using a clinical related diabetic rodent model. METHODS: We evaluated femur fracture healing by quantification of size and calcification of the callus by X-ray, histological and histochemical images, loading capacity of the fractured bone, and amount of BMP-6 in the callus and the bones using Western blot assay. RESULTS: Significant upregulation of BMP-6 in the callus and the fractured bones of both non-diabetic and the diabetic animals was observed, at the end of the second and the fourth weeks after fracture. However, significantly lower levels of BMP-6 at 35 kDa with smaller sizes of calcified callus and poor loading capacity of the healing bones were detected in the diabetic animals, compared to the non-diabetic controls. The impairment of the maturation procedure of BMP-6 (35 kDa) from precursors may be underlying the downregulation of the BMP-6 in diabetic animals. CONCLUSIONS: It could be concluded that the delayed fracture healing in the diabetic animals is correlated with deficiency of BMP-6 (35 kDa), which may be caused by impairment of maturation procedure of BMP-6 from precursors to functioning format. This is a primary study but an important step to explore the molecular pathogenesis of impairment of fracture healing in diabetes and to molecular therapeutic approach for the impairment of fracture healing.

Immediate effect of kinesiology tape on ankle stability.

BACKGROUND: Lateral ankle sprain is one of the most common musculoskeletal injuries, particularly among the sporting population. Due to such prevalence, many interventions have been tried to prevent initial, or further, ankle sprains. Current research shows that the use of traditional athletic tape can reduce the incidence of sprain recurrence, but this may be at a cost to athletic performance through restriction of motion. Kinesiology tape, which has become increasingly popular, is elastic in nature, and it is proposed by the manufacturers that it can correct ligament damage. Kinesiology tape, therefore, may be able to improve stability and reduce ankle sprain occurrence while overcoming the problems of traditional tape. AIM: To assess the effect of kinesiology tape on ankle stability. METHODS: 27 healthy individuals were recruited, and electromyography (EMG) measurements were recorded from the peroneus longus and tibialis anterior muscles. Recordings were taken from the muscles of the dominant leg during induced sudden ankle inversion perturbations using a custom-made tilting platform system. This was performed with and without using kinesiology tape and shoes, creating four different test conditions: barefoot(without tape), shoe(without tape), barefoot(with tape) and shoe(with tape). For each test condition, the peak muscle activity, average muscle activity and the muscle latency were calculated. RESULTS: No significant difference (p>0.05) was found by using the kinesiology tape on any of the measured variables while the wearing of shoes significantly increased all the variables. CONCLUSION: Kinesiology tape has no effect on ankle stability and is unable to nullify the detrimental effects that shoes appear to have.

Barbell back squat: how do resistance bands affect muscle activation and knee kinematics?

OBJECTIVES: This study aimed to determine whether looped resistance bands affect knee kinematics and lower body muscle activation during the barbell back squat. METHODS: Twenty-six healthy participants (13 female, 13 male) calculated their one repetition maximum (RM) prior to data collection. Each participant performed three squats at both 80% and 40% 1RM wearing a light resistance band, an extra-heavy resistance band and no resistance band.Vicon 3D motion analysis cameras were used to collect the kinematic data, and Delsys Trigno Lab wireless electromyography (EMG) system was used to measure vastus medialis, vastus lateralis, gluteus maximus, gluteus medius and biceps femoris muscle activity. Peak knee flexion angle, peak knee valgus angle and maximum tibial rotation values were examined. Peak EMG values were also analysed after being normalised and expressed as a percentage of maximum voluntary contraction (MVC). RESULTS: Gluteus maximus (GM) activity is significantly increased when a resistance band is used during squatting. However, squatting with a resistance band is detrimental to knee kinematics as it leads to an increase in knee valgus angle and maximum tibial rotation angle. A direct correlation is recorded between an increase in resistance and an increase in these two angles. CONCLUSIONS: Squatting with resistance bands is likely to increase the risk of knee injury. Coaches and clinicians who already implement this technique are advised to remove resistance band squats from training and rehabilitation programmes. Further research evaluating the long-term effects of using resistance bands during the barbell back squat should be considered.

Risk of periprosthetic fracture after anterior femoral notching.

BACKGROUND: Notching of the anterior femoral cortex in distal femoral fractures following TKR has been observed clinically and studied biomechanically. It has been hypothesized that femoral notching weakens the cortex of the femur, which can predispose to femoral fractures in the early postoperative period. We examined the relationship between notching of the anterior femoral cortex during total knee replacement (TKR) and supracondylar fracture. PATIENTS AND METHODS: Postoperative lateral radiographs of 200 TKRs were reviewed at an average of 9 (6-15) years postoperatively. 72 knees (41%) showed notching of the anterior femoral cortex. Notches were classified into 4 grades using the Tayside classification as follows. Grade I: violation of the outer table of the anterior femoral cortex; grade II: violation of the outer and the inner table of the anterior femoral cortex; grade III: violation up to 25% of the medullary canal (from the inner table to the center of the medullary canal); grade IV: violation up to 50% of the medullary canal (from the inner table to the center of the medullary canal) and unclassifiable. RESULTS: The interobserver variability of the classification system using Cohen's Kappa score was found to be substantially reliable. 3 of the 200 TKRs sustained later supracondylar fractures. One of these patients had grade II femoral notching and the other 2 showed no notching. The patient with femoral notching sustained a supracondylar fracture of the femur following a simple fall at home 9 years after TKR. INTERPRETATION: There is no relationship between minimal anterior femoral notching and supracondylar fracture of the femur in TKR.

Can foot angle influence the risk of injury to the lower limb joints during a field hockey hit?

OBJECTIVES: The lower limb is widely reported as the most commonly injured body part in the field of hockey, more specifically lateral ankle sprains and internal knee injury. Despite this, there remains limited understanding of how the biomechanics of the sport could be adapted to minimise injury. The aim of this study was to propose a foot position during the hockey hit that results in the smallest joint angles and moments, from a total of four different foot positions: 0°, 30°, 60° and 90°, which may correlate to injury risk. METHOD: Eighteen players from the local University Ladies Hockey Club participated in this study. Each player was required to perform a hit with their lead foot in four different positions: 0°, 30°, 60° and 90°, where 0° was a lead foot position perpendicular to the direction of motion of the ball. Angles and moments were calculated with the Vicon system using force plates and motion analysis. RESULTS: Significant differences (p<0.05) were found between the angles and moments of the four foot positions tested, indicating that foot angle can influence the degree of angulation, and moments, produced in the lower limb joints during the hockey hit. CONCLUSION: There is a relationship between lead foot position and the angles and moments produced in the lower limb joints during the hockey hit, and this may correlate with injury risk.