Heterotropic ossification (HO) is a painful tender mass that occurs in injured tissues. Pain and swelling last for weeks and are replaced by bone formation. This new bone occurs between the torn muscle fibers.

This condition is one of the most common problems after a total hip replacement. It’s directly linked to the trauma that occurs to the muscles as they are cut and/or pulled out of the way during the operation.One study reports HO in almost half (47 percent) of cases reviewed. The symptoms and the amount of soft tissue damage in HO may be mild to severe. Most cases are mild and resolve with time and treatment.

This problem may be solved in the near future with a new method of hip joint replacement. Using computer-guided imaging, doctors can make smaller openings and avoid cutting through so much soft tissue. The less trauma to the tissues, the less risk of HO.

Reference:

Anthony M. DiGioia III, MD, et al. Mini-Incision Technique for Total Hip Arthroplasty With Navigation. In The Journal of Arthroplasty. March 2003. Vol 2. Pp. 123-128.'