Kinetic and Kinematic Gait Analyses of Dogs with Undersized Cementless Stems (Biphasic Calcium Phosphate Coated) versus Cemented in Total Hip Replacement

To use kinetic and kinematic analysis to determine whether a cementless femoral implanted with a bioactive coating can be an effective alternative to a cemented femoral stem.In the Cemented group, six dogs were implanted with a 316L stainless steel hip prosthesis. The six dogs in the Cementless group were implanted with a 316L stainless steel hip prosthesis with a biphasic calcium phosphate coating. Kinetic gait analysis was performed before the surgery and at 2, 4, 6, 8, and 12 weeks postoperatively. Kinematic analyses were carried out before the surgery and at 2, 4, 6, 8, 12, and 16 weeks.A slow and sustained improvement in kinetic parameters occurred over time. Dogs implanted with the cemented prosthesis recovered normal preoperative values for maximal hip extension angle by 4 weeks after surgery. Dogs with cementless prosthesis had not recovered normal hip extension by 4 weeks. Despite this short-term change in hip mobility, there were no significant differences in gait between the two groups over the 4-month study period.No differences in gait between cementless and cemented prosthesis were observed throughout the postoperative period to the fourth month. Additionally, compensation and adaptation with gradual recovery of kinetic and kinematic parameters were evident.