Assessment of walking pattern pre and post peri-acetabular osteotomy.

BACKGROUND: Adult hip dysplasia (AHD) is a common etiology of hip pain in the young adult. Patients with adult hip dysplasia may present with hip pain and early degenerative changes resulting from elevated cumulative hip-contact stress. While there are numerous studies using radiographic parameters coupled with general and disease-specific health status measures to demonstrate that periacetabular osteotomy improves the orientation of the acetabulum, decreases pain and improves function, to our knowledge there is only one study that utilized gait analysis to demonstrate an objective functional alteration. The purpose of the present study was to prospectively evaluate the walking pattern and assess the activity level of patients undergoing periacetabular osteotomy for symptomatic adult hip dysplasia.
METHODS: Institutional review board approval was obtained for collection and review of data on 55 patients who underwent periacetabular osteotomy at one institution by the senior author (TM) between the years 2007-2009. Walking pattern characteristics were assessed including velocity, cadence, stride length of the affected side, and percent of single-limb support on the affected limb using GaitRite® walking pattern analysis. Activity was assessed as average steps/day over a consecutive seven-day period. As a secondary analysis, the disease-specific and generalized health status outcome measures of all patients who underwent periacetabular osteotomy were reviewed.
RESULTS: At an average of 11.5 months post periacetabular osteotomy the walking patterns of 27 patients were available for review. Several trends were observed, including an approximate 5% increase in walking velocity (118 cm/sec to 125 cm/sec), and a 4.5 % increase in stride length (132 cm to 138 cm, p=0.01). At a mean 9.5 months following surgery, 26 patients reported an 8.75% decrease in average steps taken daily (4598 steps/day to 4196 steps/day). A significant improvement in SF-36 PC scores (p<0.01), the WOMAC hip pain and function scores (p<0.01) and the HHS (p<0.01) was noted during the same period.
CONCLUSION: At an average of 11.5 months following periacetabular osteotomy for the treatment of symptomatic hip dysplasia, a trend toward increased walking velocity and a significant increase in stride length was noted. A significant improvement in pain relief as well as improved physical function was observed in the short term. Subgroup analysis of patients without pre-existing osteoarthritis (as compared to those with pre-existing osteoarthrosis) revealed increased walking velocity, stride length of the affected limb, and percent of gait cycle in single support on the affected limb following periacetabular osteotomy. Further prospective studies are needed to fully clarify the long-term impact of the periacetabular osteotomy on patients with symptomatic hip dysplasia.