The purpose of this study was to assess the technique of ultrasonographic evaluation of anterior shoulder translation from an anterior approach.

Anterior translation in the right shoulders of 23 volunteers was evaluated using ultrasound with a 10 MHz, 6 cm wide linear transducer. A translatory force of 90 Newtons (N) was used to translate the humeral head in the adduction and internal rotation position (Position 1), while 60 N was used in the more clinically relevant position of 90° abduction and external rotation position (Position 2).

The overall intraobserver coefficients of variation ranged from 0–13% (mean 3.8 ± 2.5%) for examiner 1 and 0.5–20.9% (mean 5.1 ± 3.9%) for examiner 2. The overall interobserver variation ranged from 0–29.8% (mean 9.3 ± 7.3%). The anterior translation in Position 1 ranged from –2.6 to 12.9 mm (mean 2.1 ± 3.1 mm) for examiner I and from −4.1 to 4.7 mm (mean 1.1 ± 2.2 mm) for examiner II. The anterior translation in Position 2 ranged from −3.3 to 3.7 mm (mean 0.3 ± 1.9 mm) for examiner I and from −8.3 mm to 4.5 mm (mean −0.7 ± 2.6 mm) for examiner II. The intraclass correlation coefficients (r) for the measured anterior translation between the 2 examiners for the 2 positions were 0.029 and −0.058 respectively.

The interobserver coefficient of variation remains excessive and there was poor agreement in the measured anterior translation. The finding of negative values in the measured anterior translation despite translatory force raises further concerns about the prospective clinical use of this technique at the present moment.

Although the epidemiology and pathomechanics of shoulder injuries in throwing athletes has been wellstudied, less is known about shoulder injuries in other sports where significant loads are carried by the upper limb. We evaluated 90 professional gymnasts who participated in a regular performance schedule during the millennium celebrations in the calendar year 2000. The gymnasts were divided into Group I (n=60) who were selected and trained for 18 months, and Group II (n=30) who were ‘fast-tracked’ through recruitment and training in the final six months before performance.

At the conclusion of the performance year, athletes were assessed using a subjective questionnaire, the SF-12 general health instrument, the Oxford instability questionnaire and the Constant score. They also underwent clinical examination, hypermobility scoring and fatigue testing.

Of those surveyed, 46% complained of pain in one or both shoulders, and the majority of these received nonoperative physical therapy during the year and were able to continue performing. Five patients (6%) had refractory pain, demonstrated signs of hypermobility, abnormal joint translation and positive relocation tests, often in the absence of symptomatic instability. All were in Group II, presented in the final six months of performance and required arthroscopic treatment for complex tears involving the anterior and superior labrum, including the biceps anchor.

These results indicate that the incidence of shoulder injury is very high among professional aerial gymnasts. The underlying cause is likely to be multifactorial in these hypermobile athletes, but the findings are consistent with the concept of cumulative microtrauma to the capsulolabral complex. Acute-on-chronic injury appears to be associated with complex labral pathology which presents with pain rather than with overt instability. Our observations suggest that training and performance schedules should be carefully monitored, incorporating extended preparation and recovery, in order to reduce the risk of shoulder injury. Further work on kinematics of the shoulder during dynamic loading of the weightbearing upper limb is required.