Shoulder Instability in the Skeletally Immature Athlete

Age-Related Changes of Elastic Fibers in Shoulder Capsule of Patients with Glenohumeral Instability: A Pilot Study

Background

Recurrent shoulder dislocations occur much more frequently in adolescents than in the older population but a clear explanation of this incidence does not exist. The aim of the present study was to define the age-related distribution of the elastic fibers (EFs) in the shoulder capsule's extracellular matrix as a factor influencing shoulder instability.

Materials and Methods

Biopsy specimens were obtained from the shoulder capsule of patients divided preoperatively into three groups: Group 1 consisted of 10 male patients undergoing surgery for unidirectional traumatic anterior instability (TUBS); Group 2 consisted of 10 male patients undergoing surgery for multidirectional instability (MDI); Group 3 represents the control, including 10 patients with no history of instability. In addition to the group as a whole, specific subgroups were analyzed separately on the basis of the age of subjects: > 22 or < to 22 years. All the samples were analyzed by histochemical (Weigert's resorcinol fuchsin and Verhoeff's iron hematoxylin), immunohistochemical (monoclonal antielastin antibody), and histomorphometric methods.

Results

Both the elastin density and the percentage of area covered by EFs were significantly higher in younger subjects (<22 years old). Furthermore, the elastin density and the percentage of area covered by EFs were significantly higher in specimens of group of patients affected by multidirectional shoulder instability in comparison to the other two groups.

Conclusion

Data of the present study confirmed the presence of an age-related distribution of EFs in the human shoulder capsule. The greater amount of EFs observed in younger subjects and in unstable shoulders could play an important role in predisposing the joint to first dislocation and recurrence.

Shoulder pain and dysfunction in young surf lifesavers

OBJECTIVES

To determine the incidence and prevalence of significantly interrupting shoulder pain (SIP) in young surf lifesavers and to determine association with training dosage and the 'combined elevation test'.

PARTICIPANTS

54 surf lifesavers aged 10-18 from the Gold Coast, Australia.

METHODS AND OUTCOME MEASURES

Retrospective survey of SIP and training dosage. Cross-sectional measures of the combined elevation test.

DESIGN

Retrospective.

RESULTS

56.5% of female surf lifesavers reported a history of SIP compared to males with 48.5%. Females had a higher combined elevation score compared to males, 28.32 ± SD 8.52 cm and 26.09 ± SD 6.64 cm, respectively. Young surf lifesavers had an incidence rate of 2.1 SIP episodes per thousand hours of training, an incidence proportion of 51.9% and prevalence of 18.5%. Combined elevation had low level positive trends with training dosages and statistically significant negative correlation with board paddling sessions per week (r = -0.287, p ≤ 0.05). Those with a history of SIP had a statistically significant higher number of sessions (p = 0.008), duration (p = 0.015) and distance (p = 0.005) swimming per week.

CONCLUSION

Young surf lifesavers with a history of SIP have greater swimming dosage not associated with a decreased combined elevation score. More board paddling sessions per week decreased the combined elevation score of young surf lifesavers.