Effect of Intra-Articular Platelet-Rich Plasma (PRP) Injections on Gait Parameters and Patient-Reported Outcomes in Patients with Mild-to-Moderate Knee Osteoarthritis (Kellgren-Lawrence Grade I-II): A Prospective Single-Group Pre-Post Study

Background Platelet-rich plasma (PRP), a biological intervention promoting cartilage repair and reducing inflammation, has shown promise in improving patient-reported outcomes, but its impact on gait mechanics requires validation. The purpose of this study is to evaluate the effect of intra-articular PRP injections on gait parameters in patients with knee osteoarthritis. Methods This prospective single-group pre-post study included patients with KOA (Kellgren-Lawrence grade I-II). All included participants received a series of three intra-articular PRP injections administered monthly, with injections spaced at least a week apart and platelet concentrations maintained at ≥ 4 times baseline levels for each dose. Primary outcomes included spatiotemporal parameters (stance phase percentage, stride length, step length, walking speed, cadence, step width) and kinematics (wrist-elbow to elbow-shoulder angle, elbow-shoulder to shoulder-hip angle, shoulder-hip to hip-knee angle, hip-knee to knee-ankle angle, maximum knee extension angle, maximum knee flexion angle). Patient-reported outcomes, including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the International Knee Documentation Committee (IKDC) score, were also evaluated as key outcomes to assess knee pain, function, and specific knee-related function. Results Fourteen patients (20 knees; KL I-II KOA) completed the PRP injections. At 3 months, cadence decreased (45.27 ± 5.23 steps/min vs. 48.91 ± 6.58 steps/min, p = 0.019) while shoulder-hip to hip-knee angle (14.74 ± 0.45 vs. 12.81 ± 1.98, p = 0.003) and maximum knee flexion [55.55° (53.13–58.78) vs. 52.8° (49.15–55.95), p = 0.015] improved significantly. Both WOMAC scores and IKDC scores showed significant improvement (WOMAC: 73.6 ± 22.5 vs. 121.3 ± 23.3, p < 0.001; IKDC: 44.2 ± 6.4 vs. 37.8 ± 3.1, p < 0.001). Conclusion The combination of improved patient-reported outcomes and normalized gait parameters suggests that PRP can serve as a valuable non-surgical intervention for OA patients, particularly those with mild-to-moderate disease.