Insertion of the Coraco-acromial Ligament in the Acromion: Histologic Study of the Degenerative Endochondral Ossification

3 INSERTION OF THE CORACO-ACROMIAL LIGAMENT IN THE ACROMION: HISTOLOGIC STUDY OF THE DEGENERATIVE ENDOCHONDRAL OSSIFICATION O. Lech, MD, J. Barbosa, MD, A. Gailit, Jr, MD, and A. Marcolan, MD; Instituto de Ortopedia e Traumatologia de Passo Fundo, RS, Brazil The authors evaluate the incidence of degenerative endochondral ossification at the insertion of the coraco-acromial ligament (CAL) in the acromion in 25 anatomical specimens consecutively obtained from patients submitted to open surgical repair of full-thickness cuff tears performed from August to November of 1997. 13 (52%) were male and 12 (48%) female. The mean age was 58.8 years. The right side was predominant with 20 (80%) shoulders. According to the radiologic evaluation, there were 2 (8%) type I acromions, 17 (68%) type II, and 6 (24%) type III. All specimens had some amount of endochondral ossification at the acromial insertion of the CAL. They were classified into 3 patterns: Type A: non-organized osteoid matrix near the bone; Type B: well-organized osteoid matrix near the bone; Type C: matrix and ossification appear together. There is no correlation between the amount of ossification and the acromion curvature; type I had 1.83 mm, type II had 2.14 mm, and type III had 1.70 mm in average. In conclusion, the sub-acromial osteophyte formation has no correlation either with age, or with the acromial angulation, but there is a direct relation with the rotator cuff lesions.