Flexor hallucis longus tendon morphology in dancers clinically diagnosed with tendinopathy

PURPOSE

The unique demands of dance technique make dancers more prone to certain pathologies especially of the foot and ankle. Flexor hallucis longus (FHL) tendinopathy, colloquially known as "dancer's tendinopathy," is common in dancers and not well studied. The purpose of this study was to assess if morphological alterations in tendon structure occur as an adaptive response to dance activity by comparing the FHL tendon in dancers to non-dancers, and if pathology further alters tendon morphology in dancers clinically diagnosed with tendinopathy.

METHODS

Three groups of ten participants were recruited (healthy non-dancers, healthy dancers, and dancers with FHL tendinopathy). Ultrasound images of the FHL tendons were analyzed for macromorphology by measuring the tendon thickness. The micromorphology was analyzed by determining the peak spatial frequency radius of the tendon. Our study did find increased tendon proper and composite tendon thickness in dancers with tendinopathy but no difference between asymptomatic dancers and non-dancers.

RESULTS

There was no significant difference in micromorphology found between any of the groups. As expected, dancers with tendinopathy demonstrated increased composite tendon and tendon proper thickness however, there was no evidence of adaptive thickening of the FHL tendon as might be expected for the dance population. There was also no evidence of micromorphological changes in the presence of clinically diagnosed FHL tendinopathy.

CONCLUSION

Because of the limited normative data for this pathology, these results can help improve diagnosis and therefore treatment for dancers to decrease the impact of this injury on their careers.

Interlimb Force Coordination in Bipedal Dance Jumps: Comparison Between Experts and Novices

Bipedal tasks require interlimb coordination that improves with practice and acquisition of skills. The purpose of this study was to compare interlimb force coordination during dance-specific rate-controlled consecutive bipedal jumps (sautés) between expert dancers and nondancers. To analyze coordination of vertical ground reaction forces recorded under each leg, the vector coding approach was used. Although there were no differences in the patterns of interlimb force coordination between groups, the dancers exhibited less variability of interlimb force coordination during the transition phase from weight acceptance to propulsion as well as during the propulsion phase itself. The interlimb force coordination variability was associated with task performance only during the transition phase, which highlights the potential importance of control during this phase. In conclusion, expert dancers were better at reducing interlimb force coordination variability during the task-relevant transition phase, which was related to better performance at maintaining jump rate and jump height consistency.

Heeled Shoes Increase Knee Work Demand During Repeated Hopping in Dancers

AIMS

Dancers have high injury rates of the lower extremity. External factors such as footwear likely alter the work demands placed on the lower extremity joints when performing dance-style movements. Research on pedestrians shows an increase in knee work demand when wearing heels, which may occur in dancers as well. The purpose of this study was to assess the effect of heeled shoes on lower extremity joint work demand during a basic dance-specific jump (sauté) in dancers when compared to barefoot.

METHODS

Ten healthy, female dancers (age 25.6±4.7 yrs; height 1.7±0.1 m; weight 64.9±9.2 kg; mean years of dance training 17.6±6.4) performed repetitive vertical bipedal dance jumps (sautés) barefoot as well as wearing heeled dance shoes. Sagittal plane hip, knee, and ankle kinetics were calculated. Percentages of work done by these joints were calculated in comparison to the work done by the leg as a whole and compared between the two conditions.

RESULTS

During a dance-specific jump, the percent contribution of energy absorption was significantly different at the ankle and knee between the two conditions. The ankle contribution decreased from 50.7±6.1% in the bare condition to 34.9±5.3% in the shod condition (p=0.002), and the knee contribution increased from 38.6±3.9% barefoot to 55.1±2.8% shod (p=0.002). The same pattern was seen for energy generation, with the ankle contribution decreasing from 48.1±7.3% to 35.6±6.9% and the knee contribution increasing from 43.3±5.6% to 56.4±6.1% in the bare vs shod condition (both p=0.002). There was no significant difference in the percent contribution from the hip.

CONCLUSION

With heeled shoes, there is a shift in work demand from the ankle to the knee with no change at the hip as compared to barefoot.

Tacit knowledge--an epistemological framework and implications for research in doctors information needs

We propose an epistemological framework of medical knowledge which might guide research and attempts in fulfilling doctors information needs. Tacit knowledge is influencing information needs and medical work but it is epistemological unresolved whether it is possible to articulate all this tacit knowledge and thus making it accessible to decision support system programming. Tacit knowledge might explain the difficulties in building successful decision support systems and should be taken into account in research.

Hansen-Street nailing of fractures of the femoral shaft. A study of 70 consecutive cases

A series is presented of 70 consecutive cases of fractures of the femoral shaft fixed with the solid Hansen-Street nail. They were followed until the nail was removed and the patient fully recovered. There were no deep infections, but one pseudarthrosis. There were four cases of fat embolism. The mean time spent in hospital was 32 days, and the patients began to take full weight at an average of 14 weeks after the injury. It was concluded that Hansen-Street nailing is a safe procedure which does not demand advanced technical skills or equipment.

Posterior acromioclavicular dislocation

Posterior dislocation of the acromioclavicular joint with the lateral end of the clavicle locked behind the acromion has only rarely been described. This paper present such a case diagnosed two weeks after the shoulder was injured in an accident. The clavicle was locked behind the articular surface of the acromion, restricting the movement of the shoulder and causing considerable pain. Anteroposterior radiographs showed a high-riding clavicle but no gap in the joint, but the axial view showed the dislocation. At operation the coracoclavicular ligaments were found overstretched but not ruptured. As reduction of the acromioclavicular joint was not possible, the lateral end of the clavicle was resected. Although the result was perfect, we consider the correct treatment should be early closed or open reduction of the acromioclavicular joint.