AAOS Now

Published 1/1/2007
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Mary Ann Porucznik

Award-winning study debunks advantages of two-incision THA

Although a faster recovery is reported as one of the advantages of two-incision total hip arthroplasty (THA), two studies conducted as part of a prospective randomized clinical trial dispel that notion. The results were presented at the 2006 fall meeting of the American Association of Hip and Knee Surgeons (AAHKS).

No faster healing

The first study showed that patients who underwent a two-incision THA did not recover more quickly than those who had a mini-posterior approach. The study, which won the AAHKS Lawrence D. Dorr, MD, Award for Surgical Techniques and Technologies, was authored by Mark W. Pagnano, MD, with coauthors James Leone, MD; Arlen D. Hanssen, MD, Robert T. Trousdale, MD, and Emily Berg.

The study directly compared the two-incision THA (Mears/Berger technique) to the mini-posterior approach in similar groups of patients. Patients who received the mini-posterior approach discontinued ambulatory aids, returned to normal daily activities and climbed stairs earlier than patients who received the two-incision approach.

The study design ensured detection of even small (five-day) differences in the measures of early functional recovery, Each group of patients included 20 males and 16 females, A computerized randomization process ensured that the groups were balanced by age, gender, race, and body mass index (BMI). All patients were diagnosed with degenerative joint disease. The mean age of all patients was 66 years old (range: 40 to 85 years old). The mean BMI was 29.5 (range: 21 to 46).

All surgeries were done by a single surgeon experienced in both techniques. A milestone diary was used to determine early function. Preoperatively, and at the two-month and one-year follow-ups, SF-12 scores were determined.

“This prospective, randomized trial dispels the notion that the two-incision THA technique dramatically improves short-term recovery after THA,” reported Dr. Pagnano. “Instead, it was the mini-posterior patients who had the quicker recovery in most categories measured.”

Gait analysis shows no benefit

A second study compared two groups of patients using gait analysis and strength testing and found no significant differences between the group that had received a two-incision THA and the group that had received a mini-posterior THA. This study was also authored by Dr. Pagnano, along with coauthors R. Michael Meneghini, MD; Ken Kaufman, MD; Krista Coleman-Wood, MD, Emily Berg and Arlen D. Hanssen, MD.

This study—which was also conducted as part of a randomized, clinical trial—compared gait parameters between two groups of 10 patients each. One group had a two-incision THA and the other had a mini-posterior THA. Both groups underwent comprehensive preoperative and postoperative (8 weeks and 1 year) gait analysis and strength testing. A computerized randomization program was used to ensure that patients in both groups were balanced according to age, gender, and BMI. The mean age of the patients was 66 years old.

Gait parameters included step length, velocity, cadence, stride length, and step width recorded with the patient walking on level ground and while climbing stairs. Strength testing was done using a Biodex machine.

Both groups showed marked improvements in gait velocity, stride length, and step width at the 8-week postoperative test. The mini-posterior patients had a significant improvement in single-leg stance time, indicating less pain while walking compared with two-incision patients. There were no other significant differences between the two groups in other gait parameters or Biodex strength testing.

“This comprehensive gait analysis and strength-testing study refutes the contention that the two-incision THA technique dramatically improves short-term recovery after THA,” said Dr. Pagnano.

“A Prospective Randomized Clinical Trial Shows that Two-Incision Total Hips Do Not Recover Quicker Than Mini-Posterior Total Hips” and “No Benefit of the Two-Incision Technique over Mini-Posterior THA: A Comprehensive Gait Analysis and Strength-Testing Study” were presented at the 16th annual AAHKS fall meeting, Nov. 3 – 5, 2006. Dr. Pagnano reports royalty and research support from Zimmer and DePuy.