Objective: To research whether total hip replacement can treat patients with knee osteoarthritis. Methods: From April 2020 through August 2021, 28 patients with knee osteoarthritis were randomly selected from among those admitted to our hospital's Department of Orthopedics. The joint function and the absolute difference of lower limb length were observed and compared before and after surgery. The pre-op, 7-day, and final follow-up assessments of limb function and the overall rehabilitation effect. Results: Postoperative hip and knee range of motion was much higher than preoperative range of motion, a difference that was statistically significant (P<0.05). Immediate postoperatively, the absolute difference in lower limb length was considerably decreased compared to preoperatively (P<0.05). Scores on the visual analogue scale (VAS) and the Oswestry disability index (ODI) considerably decreased (P<0.05) 7 days after surgery and at the end of follow-up compared to preoperative values. The Pittsburgh Sleep Quality Index (PSQI) score was considerably lower 7 days after surgery and at the final follow-up as compared to the preoperative values. Specifically, the 36-item Mos Short Form Health Survey, The difference was statistically significant (P<0.05), and the SF-36 score increased considerably. Conclusion: Patients with knee osteoarthritis may benefit from total hip replacement by increasing their range of motion and balancing out the length of their legs. Even six months following surgery, it has been shown to greatly enhance patients' quality of life and lessen their level of discomfort. It is worthy of popularization and application.