Specific Shoulder Pathoanatomy in Semiprofessional Water Polo Players: A Magnetic Resonance Imaging Study

BACKGROUND: Shoulders of throwing and swimming athletes are highly stressed joints that often show structural abnormalities on magnetic resonance imaging (MRI). However, while water polo players exhibit a combination of throwing and swimming movements, a specific pattern of pathological findings has not been described. PURPOSE: To assess specific MRI abnormalities in shoulders of elite water polo players and to compare these findings with a healthy control group. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: After performing a power analysis, volunteers were recruited for this study. Both shoulders of 28 semiprofessional water polo players and 15 healthy volunteers were assessed clinically (based on the Constant score) and had bilateral shoulder MRIs. The shoulders were clustered into 3 groups: 28 throwing and 28 nonthrowing shoulders of water polo athletes and 30 shoulders of healthy control subjects. RESULTS: Twenty-eight male water polo players with an average age of 24 years and 15 healthy subjects (30 shoulders) with an average age of 31 years were examined. Compared with controls, significantly more MRI abnormalities in the water polo players' throwing shoulders could be found in the subscapularis, infraspinatus, and posterior labrum (P = .001, P = .024, and P = .041, respectively). Other structures showed no statistical differences between the 3 groups, including the supraspinatus tendon, which had abnormalities in 36% of throwing versus 32% of nonthrowing shoulders and 33% of control shoulders. All throwing shoulders showed abnormal findings in the MRI, but only 8 (29%) were symptomatic. CONCLUSION: The shoulders of semiprofessional water polo players demonstrated abnormalities in subscapularis and infraspinatus tendons that were not typical abnormalities for swimmers or throwing athletes. CLINICAL RELEVANCE: The throwing shoulders of water polo players have specific MRI changes. Clinical symptoms do not correlate with the MRI findings.