MIS/THA: complications, but shorter rehabilitation time

By Elaine Fiedler

In a comparison of minimally invasive (MIS) dual-incision total hip arthroplasty (THA) and standard posterolateral THA, researchers found that the dual-incision technique resulted in earlier returns to independent ambulation than the standard technique, although there were more complications. The results of the study were presented in Paper 199.

Mean preoperative and postoperative Harris hip scores improved from 46 to 90 points for a group of hip patients who received MIS THA and from 45 to 93 in a group of patients who had standard THA. Self-reported activities in the MIS group included slightly earlier progress in walking without support. There were five minor complications in MIS group, but only one in the standard THA group.

These initial clinical results indicated slightly earlier improvement in daily activities with the dual-incision MIS technique. This improvement, however, was counterbalanced by a higher amount of blood loss, longer operating times and an increase in complications.

Study details

Various minimally invasive approaches have been proposed as muscle-sparing techniques to reduce THA morbidity. In this IRB-approved, Level II therapeutic study, investigators compared the results from a group of patients who had dual-incision MIS THA with a similar group who had a standard THA.

The MIS THA group included 19 patients (20 hips); the standard THA group included 20 patients (20 hips). All surgeries were performed by the same surgeon. The investigators recorded various parameters for both groups, including surgery time, estimated blood loss, length of stay, and clinical outcomes.

Patient age, preoperative diagnosis, estimated intraoperative blood loss and length of hospital stay were similar for both groups. However, there was a significant difference in weight, body mass index (BMI) and operative time between the two groups.

The MIS group included 4 males and 15 females, with a mean age of 70 years (range: 47 to 82 years). The standard THA group included 10 males and 10 females, with a mean age of 66 years (range: 44 to 87 years). In both groups, 19 patients had osteoarthritis. One patient in the MIS group had inflammatory arthritis; one patient in the standard THA group had rheumatoid arthritis.

The mean estimated blood loss for the MIS group was 380 ml vs. 329 ml for the standard THA group. Hospital length of stay for patients who had MIS THA was 3.6 days, compared to a stay of 3.4 days for patients who had a standard THA.

The standard THA group had a higher mean BMI (27 kg/m2; range: 21 kg/m2 to 33 kg/m2) than the MIS THA group (24 kg/m2; range: 19 kg/m2 to 32 kg/m2). The mean surgery time for the MIS group was approximately half that for the standard THA group (46 minutes vs. 87 minutes).

“The potential advantages of these newer surgical approaches must be studied carefully and close attention must be given to the proposed early patient benefits,” wrote the authors. They also said that these benefits should be weighed against the higher complication rate. “Orthopaedic surgeons must not lose sight of the fact that long-term function and optimal alignment of the prosthesis must continue to be the main goal in total hip arthroplasty surgery.”

“New surgical approaches are not for everyone,” said Michael A. Mont, MD, one of the authors. “Initially, these approaches should be performed at centers where they can be studied. We can expect a higher complication rate during the initial learning curve of a new approach, but this should not discourage innovative attempts to improve medical care.”

The authors included Frank R. Kolisek, MD, and Nenette M. Jessup, MPH, both of Indianapolis; Michael A. Mont, MD; Phillip S. Ragland, MD; and Thorsten M. Seyler, MD, all of Baltimore.

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