Minimally Invasive Two-incision Total Hip Replacement

Evidence Review

MANAGED CARE June 2012. ©MediMedia USA

A summary of ECRI Institute’s Emerging Technology Evidence Report

Editor’s Note: Managed care leaders are striving to make evidence-based decisions about new and emerging health technology. MANAGED CARE and ECRI Institute have joined in a collaboration to bring bi-monthly summaries of the Institute’s Emerging Technology Evidence Reports. ECRI Institute is an independent nonprofit organization that researches the best approaches to improving patient care by analyzing the research literature and data on clinical procedures, medical devices, and drug therapies. This summary provides a review of the literature through August 2010.

Technology description

Minimally invasive two-incision total hip replacement involves supplanting a damaged hip socket (acetabulum) and top of the thigh bone (femoral head and neck) with a prosthesis. Minimally invasive two-incision total hip replacement involves making one 3.8 to 8 cm incision for acetabular preparation and a second 1.5 to 6 cm incision to implant the femoral prosthesis. During this procedure, the surgeon does not dissect muscles but separates them along their natural intervals using fingertips and retractors. This muscle sparing aspect is the procedure’s key distinguishing feature.

Purported advantages of minimally invasive two-incision total hip replacement or minimally invasive one-incision total hip replacement over conventional total hip replacement include the following:

Reduced muscle trauma
Less pain and blood loss
Reduced hospital stay
Better cosmesis with smaller and less visible incisions
Quicker return to work and activities of daily living

Purported advantages of minimally invasive two-incision total hip replacement over minimally invasive one-incision total hip replacement include the following:

Quicker recovery
Lower dislocation rates
Minimized muscle and tendon damage
Increased stability

A potential disadvantage of these minimally invasive approaches compared to conventional total hip replacement is the restricted view of the surgical area, which makes the procedure more difficult and increases the likelihood of femoral fractures. To enhance the surgical view, some surgeons use computer-assisted navigation software for accurate component positioning.

ECRI Institute searches identified numerous manufacturers of cemented and non-cemented femoral stems, acetabular components, computer assistance software, and specialized instruments that can be used for minimally invasive total hip replacement.

Hospitals considering offering minimally invasive two-incision total hip replacement should consider that the procedure appears to be more difficult to perform than minimally invasive one-incision total hip replacement and conventional total hip replacement. Therefore, facilities should ensure the availability of surgeon training, which is available through manufacturer-sponsored training programs. Also, operating room schedules for the orthopedic service area may be affected by introducing minimally invasive two-incision total hip replacement because the procedure may take longer to perform than minimally invasive one-incision total hip replacement.

Key questions

Findings for each of the key questions are as follows:

1. How do the clinical efficacy outcomes of minimally invasive two-incision total hip replacement compare to minimally invasive one-incision total hip replacement and conventional hip replacement?

In studies that compared efficacy outcomes of minimally invasive two-incision total hip replacement patients to minimally invasive one-incision total hip replacement patients one year after surgery, none of four studies found a significant difference between groups in function on the Harris Hip Score. None of three studies found significant differences between groups in quality of life. Two studies did not find any differences in pain between groups.

2. How do the perioperative outcomes of minimally invasive two-incision total hip replacement compare to minimally invasive one-incision total hip replacement and conventional hip replacement?

Evidence suggests that minimally invasive two-incision total hip replacement may be associated with longer operative times than either minimally invasive one-incision total hip replacement or conventional total hip replacement and greater intraoperative blood loss than minimally invasive one-incision total hip replacement, but it is not clear that the size of these differences is clinically important. Minimally invasive two-incision total hip replacement patients returned to walking sooner than minimally invasive one-incision total hip replacement patients, but the difference was half a day in one study and a day and a half in the other study reporting this outcome; therefore, the clinical importance of these results is unclear.

3. How do the adverse event rates of minimally invasive two-incision total hip replacement compare to minimally invasive one-incision total hip replacement and conventional total hip replacement?

In the studies assessed, none of the individual adverse events occurred at statistically significant different rates between groups, but the evidence base may have been underpowered to detect between-group differences of infrequent events.

4. What are the reported adverse events associated with minimally invasive two-incision total hip replacement?

Serious adverse events reported included any complication requiring reoperation, specifically implant loosening, substantial subsidence, dislocation, fracture, and deep infection or other wound problems. Deep vein thrombosis and pulmonary embolism did occur infrequently. Less serious adverse events included superficial wound infections and transient nerve symptoms.

In the United States, surgeons perform more than 250,000 total hip replacements each year. An estimated two-thirds of patients with hip arthritis may be eligible for a minimally-invasive hip replacement procedure. Experts predict that by 2030, the number of total hip replacements will increase by 174 percent to about 572,000 procedures. As the orthopedic industry intensifies its use of direct-to-patient marketing, a growing proportion of patients who need total hip replacement can be expected to request minimally invasive total hip replacement, including minimally invasive two-incision total hip replacement.

State of Evidence Base

Quantity of evidence base — Low

There are insufficient data on clinical efficacy, comparative adverse events (especially long-term), and most of the perioperative outcomes to provide sufficient data to draw conclusions about the comparison of minimally invasive two-incision surgery to either minimally invasive one-incision surgery or conventional surgery.

Quality of evidence base — Moderate

Although two high-quality randomized controlled trials were identified, most studies were nonrandomized cohort or case-controlled studies with potential sources of bias, including subjective group allocation, lack of masking or concealment of allocation, and in some cases, retrospective study design and data collection.

Consistency of evidence base — Low

Because there was so little data for most outcomes, it is not yet possible to consider this evidence base to be consistent overall. However, studies do consistently suggest no statistically significant difference in function, quality of life, or pain at one year between minimally invasive one-incision surgery and minimally invasive two-incision surgery, greater blood loss with minimally invasive two-incision total hip replacement than minimally invasive one-incision, and longer operative times for minimally invasive two-incision total hip replacement compared to minimally invasive one-incision total hip replacement or conventional surgery.

Excerpted with permission from ECRI Institute’s database of Emerging Technology Evidence Reports. To download the full report, visit www.ecri.org/managedcare [1].

For inquiries about this report or membership in ECRI Institute’s Health Technology Assessment Information Service, send e-mail to htais@ecri.org [2].