Association of high sensitivity C-reactive protein with tearing of the long head of the biceps tendon

BACKGROUND: This study proposed to investigate whether high-sensitivity C-reactive protein (hs-CRP) is an independent risk factor for long head of biceps tendon (LHBT) tear and whether hs-CRP can increase accuracy in diagnosing LHBT tear. METHODS: This study involved 582 shoulders of 557 consecutive patients who received arthroscopic examinations at the authors’ institution between January 2010 and July 2018. The strengths of associations between LHBT tear and various factors were determined by calculating the odds ratios (ORs), with 95% confidence intervals (CIs), using logistic regression analyses. The studied variables were demographic, physical, social, metabolic, comorbidity, hs-CRP, and pain on a visual analog scale (VAS) factors, as well as those related to rotator cuff tear (RCT). Significant factors in the multivariable logistic analysis were evaluated to determine their diagnostic values, including their likelihood ratios and post-test probabilities for LHBT tear. RESULTS: In the multivariable analysis, five variables were significant: age, retraction degree of Patte, subscapularis tendon tear, hs-CRP > 1 mg/L, and pain VAS (p ≤ 0.01). The best combination of determinations for diagnosing LHBT tear, which yielded a strong positive likelihood ratio of 19.07 and a high post-test probability of 96%, was age ≥ 67 years, subscapularis tendon tear, grade of Patte ≥2, hs-CRP > 1, and pain VAS ≥ 7. CONCLUSIONS: Serum hs-CRP > 1 mg/L is an independent risk factor for LHBT tear, along with the expected risk factors of age, subscapularis tendon tear, retraction degree of Patte, and pain VAS. Serum hs-CRP > 1 mg/L increases the diagnostic accuracy for LHBT tear. LEVEL OF EVIDENCE: Level IV, Clinical case series.