Hip and Knee Replacement

Orthopaedic surgeons diagnose and treat injuries and diseases of the musculoskeletal system, the system which gives the body its form and allows you to move and be active. The musculoskeletal system consists of bones, joints, muscles, tendons, ligaments and nerves. Orthopaedic surgeons may treat conditions without surgery (with medication, exercise and rehabilitation) or if necessary, with surgery. Hip replacement and knee replacement are two common surgical procedures.

Hip and knee replacement surgery are operations that are performed to repair a diseased hip or knee with an artificial joint. A total hip or knee replacement replaces the entire joint whereas a partial hip or knee replacement replaces only one of two parts of the joint. Hip or knee replacement is commonly performed for patients who have hip or knee pain and limitations in their mobility that make it difficult to perform activities of daily living. The pain and limitations may be due to arthritis or a fracture.

A primary hip or knee replacement is when a patient's natural hip or knee joint is replaced. A hip or knee replacement revision is a replacement of an artificial joint with a new joint. Hip and knee replacement revision is performed when a previously implanted joint fails or wears out, which may occur after a long period of time. Hip and knee replacement revision is a complex procedure that requires mastery of difficult surgical techniques to achieve a good result.

Procedure volume is the number of times a procedure was performed and is used to assess clinical experience and expertise. Studies have linked higher volumes with more successful outcomes for some types of procedures. The following graphs display the number of operations for four types of joint replacements performed at the University of Michigan Health System.

Total Hip Replacement Operations

Details

Why is This Measure Important?

Health systems that perform a high number of hip replacement procedures are likely to have better outcomes, such as fewer complications. Unfortunately, there is no threshold that defines high volume so it is important to consider other measures. (See "Process and “Outcomes") This is a measure of the volume, or number of operations for primary total hip replacement.

How is UMHS Performing?

Surgeons at the University of Michigan Health System perform a substantial and growing number of hip replacements, more than the number performed at many academic medical centers across the country and at many hospitals in the state of Michigan.

UMHS Source: Hospital administrative data.


Hip Replacement Revision Operations

Details

Why is This Measure Important?

Hip replacement revision is performed when a previously implanted joint fails or wears out, which may occur after a long period of time. Hip replacement revision is a complex procedure that requires mastery of difficult surgical techniques to achieve a good result.

Health systems that perform a high number of hip replacement revision operations are likely to have better outcomes, such as fewer complications. Unfortunately, there is no threshold that defines high volume so it is important to consider other measures. (See "Process" and "Outcomes") This is a measure of the volume, or number of operations for hip replacement revision.

How is UMHS Performing?

Surgeons at the University of Michigan Health System performed a substantial and growing number of complex hip replacement revision operations, more than the number performed at many academic medical centers across the country and at many hospitals in the state of Michigan.

UMHS Source: Hospital administrative data.

Total Knee Replacement Operations

Details

Why is This Measure Important?

Health systems that perform a high number of knee replacement procedures are likely to have better outcomes, such as fewer complications. Unfortunately, there is no threshold that defines high volume so it is important to consider other measures. (See "Process" and "Outcomes") This is a measure of the volume, or number of operations for primary total knee replacement.

How is UMHS Performing?

Surgeons at the University of Michigan Health System perform a substantial number of total knee replacements.

UMHS Source: Hospital administrative data.

Knee Replacement Revision Operations

Details

Why is This Measure Important?

Knee replacement revision is performed when a previously implanted joint fails or wears out, which may occur after a long period of time. Knee replacement revision is a complex procedure that requires mastery of difficult surgical techniques to achieve a good result.

Health systems that perform a high number of knee replacement revision operations are likely to have better outcomes, such as fewer complications. Unfortunately, there is no threshold that defines high volume so it is important to consider other measures. (See "Process" and "Outcomes") This is a measure of the volume, or number of operations for knee replacement revision.

How is UMHS Performing?

Surgeons at the University of Michigan Health System performed a substantial number of complex knee replacement revision operations, more than the number performed at many academic medical centers across the country and at many hospitals in the state of Michigan.

UMHS Source: Hospital administrative data.

The following graphs describe the performance of the University of Michigan Health System by measuring the extent to which we follow best practices when performing hip replacement or knee replacement surgery. These best practices are also called evidence-based processes of care. When followed, they lead to better outcomes.

Antibiotics Given at the Right Time
Higher Value = Better Performance

Details

Why is This Measure Important?

Providing antibiotics at the right time - within an hour before an operation begins - is an important step to reduce wound infections. This measure represents the percentage of patients with a primary hip replacement (total or partial) or total knee replacement who received antibiotics within an hour before the start of their operation. A higher percentage means better performance.

How is UMHS Performing?

The University of Michigan Health System has performed better than the national average reported by the federal government and achieved 100% compliance in following this best practice.

UMHS Source: Hospital administrative data and chart review.
Comparison Group Source: National average from CMS / Hospital Compare.

Antibiotics Stopped at the Right Time
Higher Value = Better Performance

Details

Why is This Measure Important?

Antibiotics are often given to patients before surgery to prevent infection. Taking these antibiotics for more than 24 hours after routine surgery is usually not necessary. Continuing the medication longer than necessary can increase the risk of side effects such as stomach aches and serious types of diarrhea. Also, when antibiotics are used for too long, patients can develop resistance to them and the antibiotics won"t work as well. A higher percentage means better performance.

How is UMHS Performing?

Though our results have been somewhat variable, the University of Michigan Health System continues to achieve a performance that is at or above the national average reported by the federal government.

UMHS Source: Hospital administrative data and chart review.
Comparison Group Source:National average from CMS / Hospital Compare.

Recommended Antibiotics Given
Higher Value = Better Performance

Details

Why is This Measure Important?

Providing the appropriate type of antibiotics is an important step to reduce wound infections. This measure represents the percentage of patients with a primary hip replacement (total or partial) or total knee replacement who received the appropriate type of antibiotic. A higher percentage means better performance.

How is UMHS Performing?

The University of Michigan Health System performance has been some what variable than the national average reported by the federal government. We continue to evaluate our findings and improve the process.

UMHS Source: Hospital administrative data and chart review.
Comparison Group Source:National average from CMS / Hospital Compare.

In this section, we evaluate the success of the hip and knee replacement procedures by measuring the occurrence of complications, specifically infections. We compare our performance to a national average, provided by the Centers for Disease Control (CDC) National Healthcare Surveillance Network (NHSN). Though the risk developing an infection differs between patients, the CDC NHSN average is not adjusted to take account of these differences.

Wound Infection - Hip Replacement
Higher Value = Better Performance

Details

Why is This Measure Important?

Complications can occur following any surgery. Infection is one such complication. Wound infections can be minimized by using antibiotics shortly before and after surgery and by using sterile surgical techniques. Some patients have a greater risk of developing a wound infection, such as patients with diabetes or who are obese and patients taking drugs that suppress their ability to fight infection. And, patients with a hip replacement revision have greater risk compared to patients who undergo primary hip replacement.

Some wound infections following hip replacement procedures are superficial and can be easily treated. Wound infections that are deep and involve the implant are more serious.

For this measure, we compare our actual rate of infection to an expected rate. A rate that is lower than the expected rate is a good result, and means that fewer patients experienced an infection than expected. The expected rate is derived from a national standard reported by the U.S. Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN). (The measure does not include patients with a partial hip replacement)

How is UMHS Performing?

The University of Michigan Health System's performance in 2013 was very good. Fewer patients experienced an infection than expected.

UMHS, through its participation in a national program called Project Joints, has initiated several steps to reduce infection rates. These include preoperative screening and decolonization of patients who carry bacteria that cause infections (that is, getting rid of the bacteria in these patients). We also implemented a preoperative skin washing protocol. At UMHS, we continually seek out best practices to improve the quality of care for our patients.

UMHS Source: Hospital chart review and Infection Control & Epidemiology department findings.
Comparison Group Source: Centers for Disease Control (CDC) National Healthcare Safety Network (NHSN) standardized ratio for surgical site infection rates across risk categories for hip prosthesis.

Wound Infection - Knee Replacement
Higher Value = Better Performance

Details

Why is This Measure Important?

Complications can occur following any surgery. Infection is one such complication. Wound infections can be minimized by using antibiotics shortly before and after surgery and by using sterile surgical techniques. Some patients have a greater risk of developing a wound infection, such as patients with diabetes or who are obese and patients taking drugs that suppress their ability to fight infections. And, patients with a hip replacement revision have a greater risk compared to patients who undergo primary hip replacement.

Some wound infections following knee replacement procedures are superficial and can be easily treated. Wound infections that are deep and involve the implant are more serious.

For this measure, we compare our actual rate of infection to an expected rate. A rate that is lower than the expected rate is a good result, and means that fewer patients experienced an infection than expected. The expected rate is derived from a national standard reported by the U.S. Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN). (The measure does not include patients with a partial knee replacement)

How is UMHS Performing?

The University of Michigan Health System's performance in 2013 was slightly above the benchmark.

UMHS, through its participation in a national program called Project Joints, has initiated several steps to reduce infection rates. These include preoperative screening and decolonization of patients who carry bacteria that cause infections (that is, getting rid of the bacteria in these patients). We also implemented a preoperative skin washing protocol. At UMHS, we continually seek out best practices to improve the quality of care for our patients.

UMHS Source:Hospital chart review and Infection Control & Epidemiology department findings.
Comparison Group Source: Centers for Disease Control (CDC) National Healthcare Safety Network (NHSN) standardized ratio for surgical site infection rates across risk categories for knee prosthesis.