Comparative Analysis of Functional Outcomes and Gait Mechanics Following Hip Arthroplasty via Modified Hardinge and Southern Approaches: A Prospective Study

Abstract Background: Surgical approach selection plays a pivotal role in determining postoperative function following hip arthroplasty. This prospective study compares functional outcomes and gait mechanics between the modified Hardinge (anterolateral) and Southern (posterior) approaches. Materials and Methods: Forty patients undergoing hip arthroplasty were enrolled and equally divided into two groups based on the surgical approach. Functional recovery was assessed using the Harris hip score (HHS), while gait parameters—including stride length, step length, gait velocity, and cadence—were measured using a standardized footprint-based method at 6 and 9 months postoperatively. Results: At 6 months, patients in the modified Hardinge group achieved a mean stride length of 98.1 cm compared to 93.2 cm in the Southern group, while at 9 months the values improved to 101.6 cm and 97.4 cm, respectively ( P < 0.001). Step length was consistently higher in the modified Hardinge group at both follow-ups ( P < 0.001). Gait velocity was superior in the modified Hardinge group (1.15 m/s vs. 1.05 m/s at 6 months; 1.21 m/s vs. 1.11 m/s at 9 months; P < 0.001), as was cadence ( P < 0.001). Range of motion, particularly in flexion, extension, abduction, and external rotation, was significantly better in the modified Hardinge group ( P < 0.001). Functional recovery, assessed by the HHS, was also higher in the modified Hardinge group (79.75 ± 3.81 vs. 75.75 ± 3.16 at 6 months; 86.05 ± 2.31 vs. 82.05 ± 2.31 at 9 months; P < 0.001). Conclusion: The modified Hardinge approach was associated with superior early functional recovery and gait normalization compared to the Southern approach, suggesting its potential benefit in patients seeking faster rehabilitation and improved gait outcomes.