Tendon mechanobiology in small-animal experiments during post-transection healing.

Ruptures to tendons are common and costly, and no clinical consensus exists on the appropriate treatment and rehabilitation regimen to promote their healing as well as full recovery of functionality. Although mechanobiology is known to play an important role in tendon regeneration, the understanding of how mechano-regulated processes affect tendon healing needs further clarification. Many small-animal studies, particularly in rats and mice, have characterized the progression of healing in terms of geometrical, structural, compositional, mechanical, and cellular properties. Some of the properties are also studied under different mechanical loading regimens. The focus of this review is to summarize and generalize the information in the literature regarding spatial and temporal differentiation of tendon properties during rodent tendon healing following full-tendon transection, as well as how this is affected by altered in vivo loading regimens.

Achilles tendon rupture--treatment and complications: a systematic review.

Achilles tendon rupture is a frequent injury with an increasing incidence. Until now, there is no consensus regarding optimal treatment. The aim of this review was to illuminate and summarize randomized controlled trials comparing surgical and non-surgical treatment of Achilles tendon ruptures during the last 10 years. Seven articles were found and they were all acceptable according to international quality assessment guidelines. Primary outcomes were re-ruptures, other complications, and functional outcomes. There was no significant difference in re-ruptures between the two treatments, but a tendency to favoring surgical treatment. Further, one study found an increased risk of soft-tissue-related complications after surgery. Patient satisfaction and time to return to work were significantly different in favor of surgery in one study, and there was also better functional outcome after surgery in some studies. These seven studies indicate that surgical patients have a faster rehabilitation. However, the differences between surgical and non-surgical treatment appear to be subtle and it could mean that rehabilitation is more important, rather than the actual initial treatment. Therefore, further studies will be needed in regard to understanding the interplay between acute surgical or non-surgical treatment, and the rehabilitation regimen for the overall outcome after Achilles tendon ruptures.

Trigger finger, tendinosis, and intratendinous gene expression.

The pathogenesis of trigger finger has generally been ascribed to primary changes in the first annular ligament. In contrast, we recently found histological changes in the tendons, similar to the findings in Achilles tendinosis or tendinopathy. We therefore hypothesized that trigger finger tendons would show differences in gene expression in comparison to normal tendons in a pattern similar to what is published for Achilles tendinosis. We performed quantitative real-time polymerase chain reaction on biopsies from finger flexor tendons, 13 trigger fingers and 13 apparently healthy control tendons, to assess the expression of 10 genes which have been described to be differently expressed in tendinosis (collagen type 1a1, collagen 3a1, MMP-2, MMP-3, ADAMTS-5, TIMP-3, aggrecan, biglycan, decorin, and versican). In trigger finger tendons, collagen types 1a1 and 3a1, aggrecan and biglycan were all up-regulated, and MMP-3and TIMP-3 were down-regulated. These changes were statistically significant and have been previously described for Achilles tendinosis. The remaining four genes were not significantly altered. The changes in gene expression support the hypothesis that trigger finger is a form of tendinosis. Because trigger finger is a common condition, often treated surgically, it could provide opportunities for clinical research on tendinosis.

Growth hormone does not stimulate early healing in rat tendons.

Growth Hormone stimulates bone growth and fracture repair. It acts mainly by increasing the systemic levels of IGF-1. Local treatment with IGF-1 appears to stimulate tendon healing. We therefore hypothesized that systemic treatment with Growth Hormone would also stimulate tendon healing. Rat Achilles tendons were transected and left to heal. 4 groups were studied. Intramuscular injections of botulinum toxin A (Botox) were used to reduce loading in 2 groups. The animals were randomized to twice daily injections of Growth Hormone (n=2×10) or saline (n=2×10), and killed after 10 days. Healing was assessed by mechanical testing. Muscle paralysis induced by Botox reduced the strength of the healing tendon by two thirds. Growth Hormone increased femoral and tibial length in the unloaded, and femoral and tibial weight in the loaded group. Body weight and muscle weight were increased in both. In contrast, there was no increase in the strength of the healing tendons, regardless of mechanical loading status. An increase in peak force of the loaded healing tendons by more than 5% could be excluded with 95% confidence. In spite of its stimulatory effects on other tissues, Growth Hormone did not appear to stimulate tendon or tendon repair.

Trigger finger and tendinosis.

The pathogenesis of trigger finger has generally been ascribed to primary changes in the pulley. Histological examination of the affected tendons has rarely been done. We studied biopsies from tendons of trigger fingers from 29 patients and compared these to biopsies from six intact tendons. We used a modified Movin score, which describes the tendinosis of the Achilles tendon. Trigger finger tendons had a high score (14.2; SD, 2.2) consistent with tendinosis, while the controls were almost normal (2.5; SD, 1.9). This suggests that the tendon is also affected, and that trigger finger is a form of tendinosis.

Elevation of systemic matrix metalloproteinases 2 and 7 and tissue inhibitor of metalloproteinase 2 in patients with a history of Achilles tendon rupture: pilot study.

OBJECTIVES: In this study, serum levels of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) between patients with a history of Achilles tendon rupture and blood donor controls were compared, and their relation to mechanical properties of the tendons during healing were studied. METHODS: More than 3 years after injury, serum levels of MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9 and MMP-13, TIMP-1 and TIMP-2 in eight patients who had Achilles tendon rupture were measured. Twelve blood donors served as controls. During the early phase of healing, the tendon modulus of elasticity was calculated from radiostereometric data and tendon cross-sectional area. RESULTS: Patients with a history of Achilles tendon rupture had increased levels of MMP-2 (median difference 10%, p=0.01), MMP-7 (median difference 15%, p=0.02) and TIMP-2 (median difference 36%, p=0.02), compared with controls. Levels of MMP-7, measured 3 years after injury, correlated inversely to tendon modulus of elasticity (r(s)=20.83, p=0.02) and positively to tendon elongation (r(s)=0.74, p=0.05) during the early phase of healing. There was a trend towards positive correlation between MMP-7 and cross-sectional area during the early phase of healing (r(s)=0.67, p=0.08). CONCLUSIONS: Patients with a history of Achilles tendon rupture appear to have elevated levels of MMP-2, MMP-7 and TIMP-2 in serum. In these pilot data, the view that the MMP-TIMP system is involved in tendinopathy is supported and that disturbances in proteolytic control might be generalised are suggested.

Effect of a general fitness program on musculoskeletal symptoms, clinical status, physiological capacity, and perceived work environment among home care service personnel.

The aim of the present controlled study was to evaluate the effect of a general fitness program, performed by an occupational health service, using pre-post assessment for a number of different outcome measures. A total of 160 employees working in the central home care service district of Umeå, Sweden were asked to participate in a program of a 1-year long exercise program. Of the 160 selected, 54 subjects declined to participate and nine subjects were rejected after a medical check up. The remaining 97 subjects participated in a schedule consisting of pre-post medical and physiotherapy examinations, questionnaires concerning sociodemography, musculoskeletal and general health complaints and work environment, physiological tests of cardiovascular fitness, and of strength and endurance of shoulder flexors and knee extensors, and registration of sick leave. The subjects were randomly assigned to an exercise (treatment) or control group. The exercise group trained twice a week for 1 year using a mixed program including exercises for coordination, strength/endurance, and fitness. The test schedule was repeated for both groups after 1 year. The exercise intervention was associated with positive changes in prevalence and intensity of musculoskeletal and psychosomatic complaints, better physiotherapy status (less muscle tightness, better neck mobility, and less tender points), increased shoulder strength and increased coordination in thigh muscles. However, the exercise group reported worse situations post-exercise concerning aspects of their physical and psychosocial work-environment (i.e., concerning ergonomy, influence, appreciation and communication with work manager), which might have been due to stress associated with the exercise situation.

The accuracy of measurements of femoral neck fractures. Conventional radiography versus roentgen stereophotogrammetric analysis.

Postoperative displacement of the femoral head center was measured in 60 intracapsular hip fractures at repeated conventional radiographic (CR) and roentgen stereophotogrammetric (RSA) examinations. The measurements of the conventional radiographs (405 pairs) were done on a digitizing table. Totally, 105 pairs of these radiographs (AP and lateral, CR) were measured by 2 observers. Manual measurements were also made on 176 pairs of the conventional radiographs. Conventional radiographs tended to overestimate or underestimate the average displacements up to about 2 mm. Two standard deviations of the differences (RSA-CR) varied from 5.8 to 9.6 mm depending on the direction of the movements. The accuracy of the measurements on conventional radiographs did not differ between the 2 examiners. The digitizing table was found to be more accurate than the manual measurements. The accuracy of conventional radiography can most likely be improved by using a strictly standardized examination technique.

Redisplacement of nailed femoral neck fractures. 4-year follow-up of 110 cases.

In 110 femoral neck fractures, we measured the articulotrochanteric distance and the anteroposterior position of the femoral head, preoperatively, postoperatively, and at a minimum follow-up of 2 years. In displaced fractures the size of the displacement could not be used to predict future incidence of fracture redisplacement or femoral head necrosis.

Hip fractures in northern Sweden 1973-1984. A comparison of rural and urban populations.

The hip-fracture incidence in persons aged 50 years and older in the two northernmost counties of Sweden was studied during three periods between 1973 and 1984. The mean age rose from 75 to 78 years, and the annual number of fractures increased from 511 to 754. Half of this increase could be attributed to demographic aging. For persons 80 years and older, the fracture incidence in 1983/84 was higher (P less than 0.01) than the fracture incidence in 1973/74. The women/men ratio was approximately 2:1 during the survey, while the ratio cervical/trochanteric fracture type changed from 1.7:1 to 1.8:1. The crude fracture incidence rate rose from 4.4 to 5.8 fractures per 1,000 women 50 years and older; the corresponding figures for men were 2.3 and 3.4. Comparison of a rural mountain population with an urban population revealed a lower age-adjusted hip-fracture incidence rate in the rural area during the final part of the study (P less than 0.001). In the rural population, there was no change in age-specific incidence during the survey, while in the urban area the age-specific incidence in person 75 years and older was higher in 1983/84 compared with 1973/74.

Displacement in femoral neck fractures. A numerical analysis of 200 fractures.

We measured the proximal-distal and anterior-posterior displacement of the femoral head in 200 femoral neck fractures. The numerical data were compared with the Garden classification. The average displacement of the Stages I and II fractures were almost equal. Moreover, the displacement of the Stage III fractures did not differ from the displacement of the Stage IV fractures. The Garden Stages I and II fractures displayed a more posterior position of the femoral head than did the normal hips. The femoral heads of Stages III and IV were situated more posterodistally than those of the Stages I and II fractures. Classification of femoral neck fractures into two groups without (Stages I and II) and with (Stages III and IV) proximal displacement is probably sufficient for clinical use.