A more normal gait at higher speeds is attained through hip resurfacing arthroplasty as compared to standard total hip arthroplasty, according to a study presented at the American Academy of Orthopaedic Surgeons 2012 Annual Meeting.
Anatole V. Wiik, MBBS and his team, performed a case control study with 63 patients – 21 total hip arthroplasty (THA), 21 hip resurfacing arthroplasty (HRA) and 21 healthy controls, all matched for age and gender, with experimental groups all being at least 24 months removed from their arthroplasties – which involved each participant using an instrumented treadmill.
“All patients had a 6-minute acclimatization period at 4 km/hour,” Wiik said. “The speed was then increased incrementally until top walking speed was obtained.”
Speed, cadence, stride length, stop length, impulse, progression angle, base of support, maximum forces at heel strike, mid-stance and push off were all measured, according to the abstract, with the procedure taking around a reported 12 minutes of continuous walking and reaching completion without difficulty.
At preferred walking speeds, the authors wrote in the abstract, the two groups were indistinguishable. Top walking speed, however, revealed that the HRA group could walk faster – achieving a mean of 2.08 m/sec, compared to the 1.89 m/sec reached in the THA group, for a difference of 9%. The difference, Wiik and his team wrote, appeared to be due to a longer stride length for the HRA group at higher speeds, along with a higher cadence.
“This was a small study, non-randomized,” Wiik said, “so conclusions must be made cautiously. However, our study was well-matched with an appropriate control group … and hip replacement patients are 9% slower.”