Physical lameness in swine still exists despite the decades of improvements in genetic, nutrition, disease, and housing management practices. Osteochondrosis (OC) is the most prevalent cause of structural lameness in growing swine and can progress to osteochondrosis dissecans (OCD) and osteoarthritis (OA). It is still unknown what exactly causes these diseases and are classified as idiopathic (disease of unknown cause or origin). Genetics could potentially contribute to these diseases. Work is being done to find a genetic basis for OC and related disorders. A single gene mutation is unlikely to explain all the factors that lead to OA disorders (it is most likely multiple gene mutations). Environmental factors thought to be important in modulation of gene expression include nutrition, disease, and housing. There is current work being done on investigating nutritional factors, and there is no evidence that OC results from infectious organisms. Different housing systems have not had any effect on the occurrence of OC. Management recommendations include selecting for extremes in growth potential, keeping pigs fit by feeding complete diets to meet all requirements, and allow adequate stocking rates.