Answer by  
                                                                                          Fleshj (403)
                                                            
                          
                          
                                                          If you already in the Navy, yes, a bad knee can lead to discharge. Normally, however, the Navy tries to fix the problem and holds onto you until they've exhausted their medical options. If your knee prevents you from performing your duties or is a long-term problem, the Navy has no choice but to medically discharge you.