Methods for treating a partial or complete rupture of cranial cruciate ligament (CrCL) damage and for preventing or delaying CrCL damage with or without synovitis in dogs are disclosed. For example, this document provides methods for using stem cells and/or progenitor cells to prevent or reduce the likelihood of CrCL rupture in the contralateral leg of mammals, especially dogs, diagnosed with CrCL rupture, as well as methods for using stem cells and/or progenitor cells to treat, delay or prevent complete CrCL rupture in mammals, especially dogs, diagnosed as having a partial CrCL rupture.
