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Total Joint Replacements and Prevention of Heterotopic Ossificans

Every day the medical world makes advances in technology with new techniques to prolong the life of a new joint and reduce the complications that can occur. Although there can be various problems after a joint replacement surgery, most can be treated. Some common obstacles encountered after a total joint replacement include dislocation, fracture, deep venous thrombosis, rheumatoid arthritis, joint stiffness, or infection. However, prior to surgery, an individual should know all the risks that involve replacing an entire joint.

There is one complication associated with total joint replacements that most people are unaware of called heterotopic ossificans or HO. This is the growth of bone in abnormal places like soft tissue caused by surgery or trauma to the body. It can occur anywhere in the body, however, the hips, knees, shoulders, and elbows are the most common locations. This condition can vary from minor to heavy growth and can be treated with physical therapy, medications, or surgery. About one-third of people who have a hip arthroplasty will get heterotopic ossfications, however most people will be asymptomatic. Symptoms of heterotopic ossificans include: decreased joint range of motion, swelling or redness to the joint, pain, or fever. Diagnostic testing includes a bone scan, x-ray, and blood tests. In the early stages, patients will have a positive diagnosis with a bone scan only and the continued growth of the bone can continue for up to 12 months after initial onset.

The cause of heterotopic ossificans is still unknown and so is the physiology. What researchers have found is that there has be an underlying trauma to the bone and the response of increased bone growth is an inflammatory response. HO also seems to be more prevalent in males versus females with the ratio being 3:1. Even though males may have increased risk for HO, females tend to have more pronounced symptoms.

Research has also shown that the bone growth with heterotopic ossificans is very metabolically active and contains more bone cells, or osteophytes, than normal bone. The osteophytes will eventually mature after 12 months and stop progressing. At this point, the individual may have more x-rays performed or be evaluated for surgery if necessary. Surgery does not necessarily reduce the pain level in the joint but it may contribute to increased range of motion.

One technique surgeons use to prevent HO is by localized radiation to the surgery site immediately post-op. This technique has been employed since the 1970s and is quick and cost-effective. Another method of effective treatment is physical therapy which is designed to work on prevention and increasing range of motion and flexibility in the joint. Research shows early intervention with physical therapy has decreased progression of ossifications and reduced secondary muscle constrictions, which are also associated in joint immobility. According to research, patients have the best outcomes with reduced pain and improved range of motion during the first 12 months of healing during physical therapy treatment.

If there are concerns about possible restricted range of motion after a total joint replacement, consulting an orthopedist could be the first step to help diagnose possible heterotopic ossificans complications. For more information regarding treatment options visit the below websites and feel free to contact one of the therapists at Mizuta & Associates PT for additional support.

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