We performed a combined retro- and prospective study of injuries in a Swedish professional, classical ballet company during 5 consecutive years. There were 390 injuries incurred by 98 dancers over a 5-year period, i.e., 0.6 injuries/1000 dance hours. Most injuries were considered to be due to overuse. The median sick leave was 2.3 weeks per injury. The foot and ankle region is vulnerable in classical ballet dancers, and overuse injuries can result in long periods of sick leave. Of the dancers employed for more than 1 year 95% were suffered injuries during the study period. We found considerable differences in the injury profile between male and female and between younger and older dancers. Male dancers suffered more frequently from acute injuries to the knee joint. Traumatic injuries were seen most frequently in male soloists. Female dancers more often suffered overuse injuries, especially to the foot and ankle region. The younger dancers more often suffered traumatic injuries, for example, ankle sprain, and also stress fractures.

The findings of this study suggest that there is a need to apply primary injury prevention in young ballet dancers. Future studies could aim to identify (1) injury risk factors and (2) injury prevention programmes that are effective at reducing injury rates in young dancers.

Recent studies have indicated an increased incidence of female athletic injuries during the luteal phase and the first days of the menstrual period. The purpose of this study was to investigate whether postural sway and knee-joint kinesthesia very during the menstrual cycle, and whether premenstrual syndrome (PMS) influences postural balance and kinesthesia. A total of 13 subjects with regular menstrual cycles participated in the study. Postural sway and kinesthesia were measured in the early follicular phase, in the ovulation phase and in the mid-luteal phase. Postural sway was measured with an ankle disc placed on a Statometer, and kinesthesia was measured with a specially designed device. Menstrual cycle phases were determined by sex hormone analyses in serum and by luteinizing hormone (LH) detection in urine. The diagnosis of PMS was made prospectively using validated daily symptom ratings. Eight of 13 women were classified as having PMS. These women had a significantly greater postural sway (p = 0.002) and a greater threshold for detection of passive motion in the knee joints (p = 0.05) than women without PMS. A tendency (p = 0.06) towards greater postural sway in the mid-luteal phase was detected among women with PMS. This may explain the finding of an increased incidence of athletic injuries in the luteal phase, reported previously.

The present study compares postural ankle stability between previously injured basketball players, uninjured players and a control/group. Postural sway was recorded and analysed by stabilometry using a specially designed computer-assisted forceplate. Recordings were obtained for 60 s on each foot. The stabilometric results in the players with no previous injuries did not differ from those in the controls. Players with a previously injured ankle differed significantly from the control group. These players had a larger mean postural sway and used a larger sway area.

We studied 19 videotaped knee arthroscopies in 19 patients with mild to moderate osteoarthritis (OA) of the knee in order to compare the intraobserver and interobserver reliability and the patterns of disagreement between four orthopaedic surgeons. The classifications of OA of Collins, Outerbridge and the French Society of Arthroscopy were used. Intraobserver and interobserver agreements using kappa measures were 0.42 to 0.66 and 0.43 to 0.49, respectively. Only 6% to 8% of paired intraobserver classifications differed by more than one category. Observer-specific disagreement was evident both within and between observers. A small, but significant, occasional variation was also seen. Although reliability may improve by an analysis of disagreement, it appears that the arthroscopic grading of early osteoarthritic lesions is inexact.