Search PubMed⌕ Search

Biomedical subjects

R J Hawkins

Publications and source records attributed to R J Hawkins.

At least 19 recordsLinked to original sources
PubMed2001

Arthroscopic visualization of the subscapularis tendon.

PURPOSE: This study was conducted to define what portion of the subscapularis tendon is visualized during standard diagnostic glenohumeral arthroscopy and to determine the distance between the inferior aspect of the visible portion of the subscapularis tendon and the axillary nerve. TYPE OF STUDY: Anatomic (cadaveric) analysis. METHODS: Six fresh-frozen human cadaveric shoulders were placed in a simulated lateral decubitus position with longitudinal traction and 45 degrees of shoulder abduction. Glenohumeral arthroscopy was performed on each specimen using a standard posterior portal for visualization. The 4 corners of the visible portion of the subscapularis were tagged with arthroscopic sutures. The shoulders were subsequently dissected. The surface area defined by the 4 suture tags and the surface area of the entire subscapularis tendon were calculated for each specimen. The dimensions of these areas and the distance between the inferior aspect of the visible portion of the subscapularis tendon and the axillary nerve were measured with calipers. RESULTS: The arthroscopically tagged portion of the subscapularis tendon represented only a small percentage (26% +/- 11%) of the entire tendon. The majority of the subscapularis tendon is veiled by the middle and inferior glenohumeral ligaments. There was a significant distance between the inferior aspect of the visible portion of the subscapularis tendon and the axillary nerve (32.8 +/- 6.0 mm). The mean height of the visible portion of the tendon represented 44% of the mean overall height of the subscapularis. CONCLUSIONS: These data suggest that arthroscopic visualization of the subscapularis is incomplete. Lesions involving the concealed portion of the subscapularis tendon may not be detected arthroscopically. The wide margin of safety between the inferior aspect of the visible portion of the subscapularis tendon and the axillary nerve is relevant to the placement of anteroinferior (trans-subscapularis) arthroscopy portals as well as to performing arthroscopic anterior capsular releases.

Arthroscopy↗
PubMed2001

Toothbrushing competency among high-risk grade one students: an evaluation of two methods of dental health education.

OBJECTIVE: To evaluate the effectiveness of two methods of dental health education (DHE) for improving toothbrushing competency among grade one students at high risk for dental diseases. METHODS: Fifty elementary schools in the former city of North York, Ontario, Canada, were assigned to one of two groups. In one group, students received a classroom-based DHE lesson that was reinforced by two small group sessions (n = 243). In the other group, students received only a single classroom-based DHE lesson (n = 206). Trained examiners assessed 11 toothbrushing skills at pre- and postintervention. RESULTS: At the preintervention test, few significant differences were found between the groups and many students did not display competency in fundamental oral health skills, such as placing a toothbrush at the gum line. Following DHE interventions, students in both groups demonstrated improvements in most skills. A significantly higher proportion of students who received both classroom and small group sessions displayed gains in competency in three skills, compared to students receiving only a classroom lesson. These skills were brushing anterior lingual surfaces, brushing posterior lingual surfaces, and brushing all areas in a routine fashion. Students receiving only a classroom session did not display greater improvements in any skill areas compared to "classroom plus small group" students. Some students in both groups still lacked fundamental skills at the end of the DHE program. CONCLUSIONS: While one must exercise caution in interpreting the results due to several methodologic limitations, findings suggest that for high-risk grade one students, a classroom-based lesson combined with small group sessions is a more effective method of improving toothbrushing skills compared to a single classroom-based lesson.

Child↗
PubMed2001

The effect of immobilization on rotator cuff healing using modified Mason-Allen stitches: a biomechanical study in sheep.

Long-term biomechanical integrity of the surgical site is crucial to the outcome of rotator cuff repair. Usually after rotator-cuff surgery, the arm is immobilized for 6-12 weeks to minimize disruption at the healing site. Unfortunately, currently there is very little clinical data on the effects of immobilization after rotator cuff surgery. This study analyzed the effect of immobilization on rotator cuff healing by comparing the healing strength of the tendon in a bone trough using a sheep model. In sixteen (16) female adult sheep, the right infraspinatus tendons were reattached into a bone trough using a modified Mason-Allen suture pattern. After surgery, each sheep was randomly assigned into either an immobilized or non-immobilized treatment group. The immobilized group was fitted with a softball taped under the foot to restrict limb movement for 6 weeks. The non-immobilized treatment group was allowed to fully bear weight on the treated shoulder. At 26 weeks, the animals were sacrificed and the surgical shoulders were harvested and stored in a -30 degrees C freezer. Biomechanical testing was performed using a MTS 809 Axial/Torsional Servohydraulic System. Special cryo-grips were used to test the infraspinatus tendon-bone interface in anatomical alignment. All samples were preloaded with 10 +/- 5 N, and then force was measured during a crosshead displacement of 500 mm/min until failure. Force and displacement were acquired at 100 Hz and used to calculate load-to-failure and stiffness of the bone-tendon interface. The load-to-failure (N) and stiffness (N/cm) were determined for both treatment groups. For the non-immobilized group, the loads to failure and stiffness means were 2571.95 +/- 329.9 N and 2319.09 +/- 457.72 N/cm. The immobilized group means were 2954.42 +/- 473.52 N (load-to-failure) and 2579.13 +/- 383.51 N/cm (stiffness). A two-tailed two-samples unequal variance student t-test with significance set at 0.05, found no significant difference between the treatment groups for load-to-failure (p = 0.2174) and stiffness (p = 0.8286).

Animals↗
PubMed2001

Arthroscopic stabilization plus thermal capsulorrhaphy for anterior instability with and without Bankart lesions: the role of rehabilitation and immobilization.

The use of thermal energy is an exciting new technology in the treatment of anterior instability with and without Bankart reconstruction. The current approach for treating anterior instability in the absence of a Bankart lesion as discussed here is to perform thermal capsular shrinkage with a monopolar RF heat probe to address laxity in the anterior capsule and the inferior glenohumeral ligaments. If a Bankart lesion is present, repair of the lesion with arthroscopic suture anchors followed by thermal capsulorrhaphy is our treatment of choice. We currently reserve open anterior reconstruction for patients with pathology inappropriate for arthroscopic techniques and in cases where arthroscopic suturing is found to be inadequate intraoperatively. Furthermore, patients who require revision and athletes who engage in contact sports are evaluated on an individual basis to ascertain if arthroscopic techniques are appropriate (CD-2.1). Nonetheless, basic science research has revealed the importance of a formal period of immobilization followed by guarded mobilization. By using the aforementioned algorithm and postoperative protocol, low recurrence rates have been achieved while at the same time maintaining motion in the functional range. Of course, further follow-up, more patient studies, and peer review publications are required to determine if thermal capsulorrhaphy can replace open procedures as the gold standard for addressing capsular laxity associated with anterior instability.

Arthroscopy↗
PubMed2000

Oral hygiene knowledge of high-risk Grade One children: an evaluation of two methods of dental health education.

The effectiveness of two methods of dental health education (DHE) for improving oral hygiene knowledge among high-risk Grade One students was evaluated. Fifty elementary schools in the former City of North York, Canada were assigned to one of two groups. In one group, students received a classroom-based DHE lesson which was reinforced by two small-group sessions (n=243). In the other group, students received only a single classroom-based DHE lesson (n=206). After DHE interventions, students in both groups displayed improved knowledge for most oral hygiene questions (e.g., when should you throw your toothbrush away?). However, for several questions, a significantly higher proportion of "classroom plus small-group sessions" students displayed improved knowledge compared to students receiving only a classroom lesson. These items included: awareness that cavity prevention and removal of germs are two purposes of oral hygiene; and knowledge that teeth help people to eat and talk. Results suggest a classroom-based lesson combined with small-group sessions is a more effective method of improving oral hygiene knowledge among high-risk Grade One students compared to a single classroom-based lesson.

Child↗
PubMed1999

Open shoulder instability surgery. Complications.

Surgical stabilization of the shoulder can be a challenging procedure. Complications can and do occur, even in the hands of the most experienced surgeons. Emphasis must be placed on proper diagnosis, appropriate technique, and an understanding of potential complications to maximize the likelihood of a successful surgical outcome. The authors hope that this review helps to outline the complications that can occur with open instability surgery. Only by understanding the complications associated with the procedures performed can surgeons hope to decrease the frequency of their occurrence.

Arthritis↗
PubMed1999

Prospective analysis of ice hockey injuries at the Junior A level over the course of one season.

OBJECTIVE: This study was conducted to identify the circumstances, timing, frequency, and types of injuries for a Junior A hockey team in an attempt to develop injury prevention strategies. DESIGN: This study was a prospective review of injuries sustained by a hockey team during one season. SETTING: Players were evaluated in a private practice clinical setting and during practices and games. PARTICIPANTS: Twenty-two hockey players (16-20 years old) were evaluated. An injury was defined as any event requiring the attention of a physician or trainer. The players sustained 83 injuries throughout the course of the season. Seventy-four were considered independent events. MAIN OUTCOME MEASURES: The effects of the following variables on injury rates were analyzed: position, game situation versus practice, and timing of injury during the game. RESULTS: Players were 20 times more likely to injure themselves during a game than practice. Although forwards sustained the highest total percentage of injuries, defensemen had the highest incidence of injury in games. More injuries occurred in the later periods and in the later minutes of each period. Injury incidence decreased for the second half of the season compared with the first half. CONCLUSION: Our data suggest goaltenders are at the lowest risk of sustaining an injury, but forwards appear to be at a higher risk in practice situations and defensemen in games. Game situations place players at a much greater risk of injury than practice sessions, particularly in the later portions of each period and toward the end of the game. Given the propensity for injury in the early season and later in the game, endurance training before and during the season may be important in injury prevention.

Adolescent↗
PubMed1999

Treatment of symptomatic glenoid loosening following unconstrained shoulder arthroplasty.

Nine patients with symptomatic glenoid loosening were identified and ultimately underwent surgical revision. Preoperative assessment demonstrated that pain, decreased range of motion, and functional disability were common features. A painful clunking sensation with forward elevation of the arm was noted in four of the nine patients. At surgical revision, a grossly loose glenoid component was found in all cases and removed. Seven of the nine patients underwent revision using another cemented glenoid component, and two patients were left with a hemiarthroplasty due to glenoid bone deficiency. Results following revision surgery demonstrated increased range of motion, decreased pain, and increased functional ability with good overall patient satisfaction in seven of nine patients. Two patients in whom revision glenoid components were implanted were considered failures due to recurrent loosening. Although revision of the glenoid component is often technically feasible, recurrent loosening may occur. Revision to a hemiarthroplasty may be an acceptable alternative to glenoid replacement.

Activities of Daily Living↗
PubMed1999

Role of MR imaging in the management of "skier's thumb" injuries.

"Skier's thumb" is an acute rupture of the ulnar collateral ligament (UCL) of the metacarpophalangeal (MCP) joint of the thumb. As the method of choice in evaluating soft tissue injuries, MR imaging is useful in evaluating UCL injuries. This article reviews current concepts regarding the rupture of the UCL, including a study of 34 UCL injuries in which MR imaging was used as the main diagnostic tool. When correlated with surgical findings, MR imaging resulted in identifying UCL tears with 96% sensitivity and 95% specificity.

Adult↗
PubMed1999

Role of MR imaging in the management of injuries in professional football players.

This article discusses the effectiveness of MR imaging in evaluating the injuries of both upper and lower extremities in the professional football player. Topics include bone, joint and soft tissue disorders, and injuries resulting from overuse or trauma of the shoulder, elbow, forearm, and wrist; the pelvis and hip, lower extremity muscle and tendon, knee, and ankle.

Arm Injuries↗
PubMed1999

Preventive health care, 1999 update: prevention of oral cancer mortality. The Canadian Task Force on Preventive Health Care.

BACKGROUND: Approximately 3,000 new cases of oral cancer are diagnosed each year in Canada. Most of these cases occur among older adults with a history of tobacco use or excessive alcohol consumption. Preventive interventions for oral cancer include counselling of patients to modify risk factors and screening to identify precancerous and early-stage lesions. This report presents evidence-based guidelines on the prevention of oral cancer and precancer among asymptomatic patients. METHODS: Literature searches of the 1966-1999 MEDLINE and CANCERLIT databases were completed using the major MeSH heading mouth neoplasms. References from articles and recommendations of organizations were also reviewed. The evidence-based methods of the Canadian Task Force on Preventive Health Care were used to assess evidence and to develop guidelines. Advice from experts and other recommendations were taken into consideration. RESULTS: In cohort and case-control studies, smoking cessation decreased the risk of oral cancer and precancer. Randomized controlled trials (RCTs) indicate counselling by trained health care professionals is effective in promoting smoking cessation. Although counselling has been effective for the reduction of excessive alcohol consumption in RCTs, no studies have examined whether alcohol reduction reduces the risk of oral cancer or precancer. The usefulness of general population screening is limited by the low prevalence and incidence of the disease, the potential for false-positive diagnoses and the poor compliance with screening and referral. There is no evidence that screening of the general population or high-risk groups leads to a reduction in mortality or morbidity from oral cancer. INTERPRETATION: There is good evidence to specifically consider smoking cessation counselling in a periodic health examination (grade A recommendation). For population screening, there is fair evidence to specifically exclude screening for oral cancer (grade D recommendation). For opportunistic screening during periodic examinations, there is insufficient evidence to recommend inclusion or exclusion of screening for oral cancer (grade C recommendation). For patients at high risk, annual examination by physician or dentist should be considered. Risk factors include tobacco use and excessive consumption of alcohol. These recommendations are similar to those made by the Canadian Task Force on the Periodic Health Examination in 1994 and by the U.S. Preventive Services Task Force in 1996.

Adult↗
PubMed1999

Comparison of tunnel suture and suture anchor methods as a function of time in a sheep model.

There is little quantitative information available on the required healing time after a rotator cuff surgery. This study evaluated two surgical procedures by comparing the healing strength as a function of time of the tendon in a bone trough using a sheep model. The two surgical procedures compared were bioabsorbable suture anchors and bone tunnel suture technique. The infraspinatus tendon was split in half and procedure (suture anchor/tunnel suture) locations were randomly allocated to the proximal or distal half of the tendon at the healing time points of 0, 3, 6, 9, and 12 weeks with n = 6 at t = 0 and n = 8 in all other groups. At each time point, the surgical (right) and normal (left) shoulders were harvested and stored in a -30 degrees C freezer until testing. Biomechanical testing was performed using a MTS 809 Axial/Torsional Servohydraulic System. Special cryo-grips designed and built to test the infraspinatus tendon-bone interface in anatomical alignment were used. All samples were preloaded with 5 Newtons, and then force was measured during a crosshead displacement of 50 cm/min until failure. Force and displacement data were recorded to calculate load to failure and stiffness of the bone-tendon construct. There was only significant difference (95% CI) in mean tensile force at week 0, with the bone tunnel suture technique tensile force greater than the suture anchor method tensile force (p = 0.0261). There was no significant difference between stiffness means at any of the survival times.

Animals↗
PubMed1998

Revision of failed total shoulder arthroplasty.

The complexity of revision shoulder surgery remains a supreme challenge for the experienced shoulder surgeon. The difficulty of surgery is often accompanied by unpredictable patient cooperation during the postoperative rehabilitation program. Recognition of the problems associated with the failed shoulder arthroplasty is necessary for successful revision surgery. Numerous reconstructive techniques are necessary for restoration of soft tissue and bony deficiencies. Component revision is often necessary in treating component loosening or glenohumeral instability. Glenoid component removal may be necessary in the presence of severe rotator cuff insufficiency or marked glenoid bone deficiency. Humeral revision is most predictably treated with methylmethacrylate fixation. Humeral fractures associated with humeral arthroplasty are most successfully treated surgically, except in those instances where a long oblique or spiral fracture is not associated with prosthetic loosening. Deep infection is most predictably treated by extensive debridement, parenteral antibiotics, and delayed exchange of the components. The success of revision shoulder arthroplasty is often unpredictable, with 60% of revisions offering satisfactory pain relief and restoration of function. Critical to the success of revision arthroplasty is the status of the soft tissues, particularly the anterior deltoid and rotator cuff.

Anti-Bacterial Agents↗
PubMed1998

An update of mechanical oral hygiene practices: evidence-based recommendations for disease prevention.

PURPOSE: This review updates the mechanical oral hygiene practices discussed at a 1986 State-of-the-Science Workshop. METHODS: The 1984-1995 MEDLINE database was searched and appropriate studies that used disease outcome measurements were located and selected. Recommendations were made based on the levels of evidence concept. RECOMMENDATIONS: 1) There is good evidence to recommend: toothbrushing twice daily with fluoridated toothpaste; using oscillating-rotating or counter-rotational-action electric toothbrushes; flossing for adults; personal supragingival irrigation as an adjunct to toothbrushing; and scaling of disease active sites for the treatment of periodontal diseases. 2) There is moderate evidence to recommend: using any soft-bristled manual toothbrush; using wooden interdental cleaners; scaling of disease active sites every three to four months for patients with histories of moderate/severe periodontitis; scaling of disease active sites at intervals of > or = 6 months for most patients, based on patient need; and removal of restoration overhangs. 3) There is moderate evidence to not recommend: use of vibrating, rotating or sonic action electric toothbrushes; using foam brushes; flossing for children; using interdental brushes; gingival massage; and tongue brushing or scraping. 4) There is good evidence to not recommend: subgingival scaling for patients with no signs of active disease; and polishing for disease prevention. CONCLUSIONS: Consistent with the 1986 workshop report, the 1996 recommendations emphasize the importance of personal oral hygiene and the provision of professional treatment when personal care fails to prevent disease.

Adult↗
PubMed1997

The normative need for tooth extractions in older adults in Ontario, Canada.

OBJECTIVE: To determine the reasons for clinically defined need for tooth extractions were examined. DESIGN: Descriptive survey; interview and clinical data. SETTING: The City of North York, Canada. SUBJECTS: 1,531 dentate adults aged 65 and over, 69% being nursing home residents. MEASUREMENTS: Age, sex, type of residence and dental attendance pattern. OUTCOME MEASURE: Normative need for tooth extraction. RESULTS: One or more extractions were required by 38% of nursing home residents and 21% of independently-living subjects. The mean number of teeth indicated for extraction were 1.4 and 0.6, respectively. Among nursing home residents, caries was more often the reason for extraction for almost all tooth types, but for independently-living subjects periodontal reasons were more common. Overall, a significantly higher proportion of nursing home residents needed extractions due to both caries and periodontal reasons (25% and 16%) compared to subjects who lived independently (10% and 11%). For nursing home residents in all age groups, more subjects required caries-related extractions, but for independently-living subjects about equal proportions required extractions due to caries and periodontal diseases. Although the percentage of subjects requiring extraction due to caries varied significantly by age and residence type, the percentage needing extractions due to periodontal diseases showed slight variation and remained under 20%. CONCLUSION: This study indicates that among high risk groups of older adults caries continues to be the major reason for tooth extraction. However, problems with sampling limit the external validity of these results.

Adult↗
PubMed1997

Three-year coronal caries incidence in older Canadian adults.

This paper describes the incidence of coronal caries in a sample of older adults. A 3-year follow-up study was conducted of 493 community-dwelling adults aged 50 years and over in Ontario, Canada. The incidence of coronal caries was 57.0%, and the mean net DFS increment was 1.9 surfaces. In bivariate analysis, several variables were significantly associated with incidence and/or mean DFS increment. These included: age, marital status, baseline coronal DFS, number of teeth at baseline, mean periodontal attachment loss of 4 mm or more, and wearing partial dentures. In logistic regression analysis only four factors had significant independent effects. These were level of education, marital status, mean periodontal attachment loss and number of teeth at baseline. The predictive ability of this model was fair: accuracy 65.7%, sensitivity 80.2%, and specificity 46.2%. When logistic analysis was repeated separately for two age groups, different predictors had significant independent effects, and sensitivity and specificity values differed substantially. These findings indicate predictive models for caries incidence should include both clinical and non-clinical variables because both types of variables may help to explain different aspects of coronal caries experience. Further research is required to identify other factors associated with coronal caries in older adults.

Age Factors↗
PubMed1997

A survey of general dentists in Ontario, Part II: Knowledge and use of topical fluoride and dental prophylaxis practices.

A mail questionnaire was used to assess variations in the knowledge and practices of Ontario dentists with respect to topical fluoride and prophylaxis procedures. The questionnaire was answered by 1,276 general dentists. A high percentage (72 to 83 per cent) of respondents identified six months as the optimal time interval at which both procedures should be repeated for all patients under 19 years of age. Relatively few dentists (< 10 per cent) indicated that there should be no specific time interval for re-treatment (i.e. that it should be individually selected). The respondents' preventive knowledge was found to be deficient in two areas: few dentists (16 per cent) knew that it is not necessary to provide a prophylaxis prior to topical fluoride application to achieve maximum caries protection; and most dentists overestimated the speed of caries progress from outer enamel to the dentinoenamel junction (DEJ) in both primary (83 per cent) and permanent (82 per cent) approximal tooth surfaces. In bivariate analysis, three variables were found to be consistently and significantly related to optimal time intervals selected for both topical fluoride application and prophylaxis procedures: year of graduation from dental school; level of hygienist employment; and percentage of patients with private insurance. Multivariate analysis also identified three significant variables: year of graduation from dental school; level of dental hygienist employment; and practice business. Continuing education courses are suggested as a means of updating dentists' knowledge regarding preventive services. Studies are needed to determine the extent to which recent recommendations regarding the professional application of topical fluorides have been followed.

Adolescent↗