Guy Trudel

Early reattachment does not reverse atrophy and fat accumulation of the supraspinatus--an experimental study in rabbits.

Introduction: Reattachment of the supraspinatus (SSP) tendon after spontaneous rupture leads to improved shoulder function. Whether this improvement of function is due to a reversal of muscle atrophy and fat accumulation known to occur after SSP rupture is still debated. Our previous study of late reattachment of SSP (12 weeks) failed to confirm a reversal of muscle atrophy and of fat accumulation.

Histologic evidence of degeneration at the insertion of 3 rotator cuff tendons: A comparative study with human cadaveric shoulders

We determined on histologic examination the degree of degeneration at the insertion of 3 rotator cuff tendons in 76 cadaveric shoulders, 17 of which had a partial tear of the supraspinatus. Fiber thinning, the presence of granulation tissue, and incomplete tearing of fibers, all evidence of degeneration, were quantified separately for each tendon. Among the shoulders that were intact on macroscopy, no significant difference in degeneration score could be found. In all 3 tendons degeneration was more prominent on the articular sides compared with the bursal sides (P < .0001). The degeneration score of partially torn supraspinatus was significantly higher than that of the intact tendons (P < .0001). The extent of granulation tissue, 1 criterion of degeneration, seemed to contribute mostly to this difference. Intrinsic degeneration occurred foremost in the articular side of the rotator cuff and might constitute the primary cause of rotator cuff tearing.

Joint contracture following prolonged stay in the intensive care unit

Background: Prolonged immobility during a critical illness may predispose patients to the development of joint contracture. We sought to document the incidence of, the risk factors for and the reversibility of joint contractures among patients who stayed in a tertiary intensive care unit (ICU) for 2 weeks or longer. Methods: We conducted a chart review to collect data on the presence of and risk factors for joint contractures in the shoulders, elbows, hips, knees and ankles among patients admitted to the ICU between January 2003 and March 2005. Results: At the time of transfer out of the ICU, at least 1 joint contracture was recorded in 61 (39%) of 155 patients; 52 (34%) of the patients had joint contractures of an extent documented to impair function. Time spent in the ICU was a significant risk factor for contracture: a stay of 8 weeks or longer was associated with a significantly greater risk of any joint contracture than a stay of 2 to 3 weeks (adjusted odds ratio [OR] 7.09, 95% confidence interval (CI) 1.29–38.9; p = 0.02). Among the variables tested, only the use of steroids conferred a protective effect against joint contractures (adjusted OR 0.35, 95% CI 0.14–0.83; p = 0.02). At the time of discharge to home, which occurred a median of 6.6 weeks after transfer out of intensive care, 50 (34%) of the 147 patients not lost to follow-up still had 1 or more joint contractures, and 34 (23%) of the patients had at least 1 functionally significant joint contracture. Interpretation: Following a prolonged stay in the ICU, a functionally significant contracture of a major joint occurred in more than one-third of patients, and most of these contractures persisted until the time of discharge to home.

Early reactions after reimplantation of the tendon of supraspinatus into bone: A STUDY IN RABBITS

In 14 rabbits we determined the origin of the cells effecting healing of the tendon of supraspinatus inserted into a bony trough. After two weeks both the cellularity of the underlying bone and the thickness of the subacromial bursa were significantly increased in the operated compared with the control shoulders. The cellularity of the stump of the tendon, however, was significantly decreased in the operated shoulders. In this model, both the underlying bone and the subacromial bursa but not the stump of the tendon contributed to the process of repair. We conclude that the medial stump should be debrided judiciously but that cutting back to bleeding tissue is not necessary during repair of the rotator cuff. Moreover, great care should be taken to preserve the subacromial bursa since it seems to play an important role in the healing process.

Physical Inactivity Differentially Alters Dietary Oleate and Palmitate Trafficking

OBJECTIVE— Obesity and diabetes are characterized by the incapacity to use fat as fuel. We hypothesized that this reduced fat oxidation is secondary to a sedentary lifestyle. RESEARCH DESIGN AND METHODS— We investigated the effect of a 2-month bed rest on the dietary oleate and palmitate trafficking in lean women (control group, n = 8) and the effect of concomitant resistance/aerobic exercise training as a countermeasure (exercise group, n = 8). Trafficking of stable isotope–labeled dietary fats was combined with muscle gene expression and magnetic resonance imaging–derived muscle fat content analyses. RESULTS— In the control group, bed rest increased the cumulative [1-13C]oleate and [d31]palmitate appearance in triglycerides (37%, P = 0.009, and 34%, P = 0.016, respectively) and nonesterified fatty acids (NEFAs) (37%, P = 0.038, and 38%, P = 0.002) and decreased muscle lipoprotein lipase (P = 0.043) and fatty acid translocase CD36 (P = 0.043) mRNA expressions. Plasma NEFA-to-triglyceride ratios for [1-13C]oleate and [d31]palmitate remained unchanged, suggesting that the same proportion of tracers enters the peripheral tissues after bed rest. Bed rest did not affect [1-13C]oleate oxidation but decreased [d31]palmitate oxidation by −8.2 ± 4.9% (P < 0.0001). Despite a decreased spontaneous energy intake and a reduction of 1.9 ± 0.3 kg (P = 0.001) in fat mass, exercise training did not mitigate these alterations but partially maintained fat-free mass, insulin sensitivity, and total lipid oxidation in fasting and fed states. In both groups, muscle fat content increased by 2.7% after bed rest and negatively correlated with the reduction in [d31]palmitate oxidation (r2 = 0.48, P = 0.003). CONCLUSIONS— While saturated and monounsaturated fats have similar plasma trafficking and clearance, physical inactivity affects the partitioning of saturated fats toward storage, likely leading to an accumulation of palmitate in muscle fat.

High collagen type I and low collagen type III levels in knee joint contracture: an immunohistochemical study with histological correlate.

We studied the levels of collagen type I and type III in the knee joints of rats immobilized for periods of 2, 4, 16 and 32 weeks and sham-operated controls. The intensities of immunostaining of the anterior and posterior synovial intima, anterior and posterior subintima, and patellar tendon were graded on a scale from 0 to 3. We found higher type I collagen levels in immobilized legs than in sham-operated legs in the anterior subintima after 4 and 16 weeks (mean score 2.1 vs 1.3, 2.2 vs 1.3, respectively) and posterior subintima after 2, 4 and 16 weeks of immobility (2.4 vs 1.7, 2.3 vs 1.5, 2.2 vs 1.3, respectively). Lower type III collagen levels were found in immobilized legs than in sham-operated legs in the anterior synovial intima after 32 weeks (1.3 vs 2.3), and posterior synovial intima and posterior subintima after 16 weeks of immobility (1.4 vs 2.8, 1.2 vs 1.7, respectively). The higher type I collagen levels in the subintima combined with lower type III suggests that the contracture process is marked by fibrosis, not new tissue proliferation. In this respect, contractures differ from granuloma, scar tissue and the pannus of inflammatory arthritis.

Extent and Direction of Joint Motion Limitation After Prolonged Immobility: An Experimental Study in the Rat

OBJECTIVES To test the hypotheses that contractures progress at different rates in relation to the time after immobilization, that immobilization in flexion leads to loss of extension range of motion, and that joints of sham-operated animals are better controls than the contralateral joint of experimental animals. STUDY DESIGN Experimental, controlled study in which 40 adult rats had one knee joint immobilized at 135 degrees of flexion for up to 32 weeks and 20 animals underwent a sham procedure. At intervals of 2, 4, 8, 16, and 32 weeks, 8 experimental and 4 sham-operated animals were killed and their knee motion measured in flexion and extension. RESULTS In the experimental group, the range of motion decreased in the first 16 weeks of immobility at an average rate of 3.8 degrees per week (p<.0001) to reach 61.1 degrees of restriction. A plateau was then observed from which the contracture did not progress further. The loss in range of motion occurred in extension, not in flexion. CONCLUSION This study defined an acute stage of contractures starting at the onset of immobility and lasting 16 weeks, during which the range of motion was progressively restricted, and a chronic stage during which no additional limitation was detected. The loss in motion was attributed to posterior knee structures not under tension during immobilization in flexion. Contrary to the hypothesis, the contralateral joint was validated as a control choice for range-of-motion experiments.

Localized and adaptive synoviocyte proliferation characteristics in rat knee joint contractures secondary to immobility

OBJECTIVE To investigate the proliferative activity of synoviocytes in joint contracture. DESIGN Experimental controlled trial. SETTING Laboratory in vivo study. ANIMALS Adult male Sprague-Dawley rats (avg weight, 340g). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES We immobilized the knee joints of 24 rats, in 135 degrees of flexion, for up to 32 weeks. Controls were 24 sham-operated and 5 unoperated rats. On sagittal sections, synoviocytes that stained with a proliferating cell nuclear antigen antibody were counted over the anterior and posterior synovial intima. The length of the synovial intima was also measured. RESULTS The absolute number of proliferating synoviocytes decreased markedly in the posterior capsule of knee joints immobilized for more than 2 weeks (2.4+/-1.0 vs 22.7+/-7.1 at week 16, P<.05), and so did the synovial intima length (1.4+/-0.1mm vs 8.6+/-0.5mm at week 16, P<.05). No change occurred anteriorly. CONCLUSION A decreased number of proliferating synoviocytes and increased intima adhesion in the posterior capsule characterized joint contractures. The data further suggest that the synovial intima adapted to the new position of the joint. Phenomena of mechanotransduction could explain the fact that adaptations were restricted to the posterior synovial intima.

Structural disorders at the insertion of the supraspinatus tendon: Relation to tensile strength

We examined macroscopically and microscopically 55 cadaver rotator-cuff tendons attached to their humeral heads to determine the distance between the edge of the articular cartilage and the tendon insertion of the supraspinatus (the width of the sulcus) and the score of regressive changes at the sulcus. In 33 specimens we measured the tensile strength. The width of the sulcus was correlated with the score of regressive changes and with the ultimate tensile strength of the supraspinatus tendon. The width of the sulcus correlated positively with the score of regressive changes (r = 0.66, p < 0.0001), but there was a negative correlation between the latter and the ultimate tensile strength (r = -0.81, p = 0.001) and between the width of the sulcus and the ultimate tensile strength (r = -0.74, p = 0.004). We believe that the width of the sulcus is a simple and useful clinical indicator of the integrity and the tensile strength of the supraspinatus tendon.

Effects of Rear-Wheel Camber on Wheelchair Stability

OBJECTIVES To evaluate how using a wheelchair with rear-wheel camber (when the bottoms of the wheels are farther apart than the tops) is associated with the risk of instability incidents, and to determine the effect of camber on wheelchair stability. DESIGN, SETTING, PATIENTS Epidemiologic data were analyzed from a sample of 576 users of manually propelled wheelchairs in Nova Scotia. A controlled trial was performed using a representative wheelchair occupied by an anthropomorphic test dummy, altering the camber in 5 degrees increments from -15 degrees to +15 degrees. MAIN OUTCOME MEASURES For the epidemiologic study, univariate and multivariate analyses were used. To measure the static stability, a tilting platform was used according to the guidelines of the International Organization for Standardization. RESULTS Camber users reported significantly more instability incidents; of these incidents, more were in the rear direction (40% vs 27%) and fewer in the lateral direction (17% vs 28%) (p < .01). When controlling for other factors, camber was associated with a 3.91-fold increased risk of sustaining an instability incident (p < .001). With increases in camber angle in the laboratory, lateral and forward stability increased and rear stability decreased (with the wheels unlocked and locked) (p < .001). CONCLUSION Camber use is negatively associated with instability incidents in the lateral direction and positively associated with incidents in the backward direction, probably due in part to the effects of camber on lateral and rear stability.