Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Background The risk of noncontact ACL injury reportedly is increased in patients with a greater posterior tibial slope (PTS), but clinical data are inconsistent. It is unclear whether the medial and lateral PTSs have a different impact on this connection. It also is unknown whether the meniscal slope (MS) is associated with ACL injury. Patients/methods Using MRI, we compared the medial and lateral PTSs and MSs separately in 55 matched pairs of patients with isolated noncontact ACL injuries and a control group.

Chronic rotator cuff tendon tears lead to fatty infiltration and muscle atrophy with impaired physiological functions of the affected muscles. However, the cellular and molecular mechanisms of corresponding pathophysiological processes remain unknown. The purpose of this study was to characterize the expression pattern of adipogenic (PPARg, C/EBPb) and myogenic (myostatin, myogenin, Myf-5) transcription factors in infraspinatus muscle of sheep after tenotomy, implantation of a tension device, refixation of the tendon, and rehabilitation, reflecting a model of chronic rotator cuff tears. In contrast to human patients, the presented sheep model allows a temporal evaluation of the expression of a given marker in the same individual over time. Semiquantitative RT/PCR analysis of PPARgã , myostatin, myogenin, Myf-5, and C/EBPb transcript levels was carried out with sheep muscle biopsy-derived total RNA. We found a significantly increased expression of Myf-5 and PPARg after tenotomy and a significant change for Myf-5 and C/EBPb after continuous traction and refixation. This experimental sheep model allows the molecular analysis of pathomechanisms of muscular changes after rotator cuff tear. The results point to a crucial role of the transcription factors PPARg, C/EBPb, and Myf-5 in impairment and regeneration of rotator cuff muscles after tendon tears in sheep. ß