Purpose. This work is aimed at determining the application value of platelet-rich plasma (PRP) therapy plus total knee arthroplasty (TKA) in traumatic arthritis (TA) of the knee. Methods. A retrospective study was conducted on 78 cases of TA of the knee admitted between March 2021 and January 2022 to the Quanzhou First Hospital Affiliated to Fujian Medical University. Based on different treatment methods, 38 cases treated with TKA were assigned to the control group, and 40 cases intervened by PRP+TKA were included in the observation group. The operation time (OT), drainage volume (DV), total blood loss (TBL), incision inflammatory reaction rate, and grade A healing rate were recorded. Besides, preoperative and postoperative knee joint Hospital for Special Surgery (HSS) scores, knee joint pain assessed by visual analogue scale (VAS), knee joint range of motion (ROM), and bone metabolism parameters (osteocalcin (OST), total N-terminal propeptide of type I procollagen (tPINP), and β-isomerized C-terminal telopeptides (β-CTX)) were recorded. Results. The observation group showed reduced postoperative DV and TBL than the control group (
P
<
0.05
). The two cohorts differed insignificantly in OT, incision inflammatory response rate, and grade A healing rate (
P
>
0.05
). The observation group also had better improvement in the HSS score, pain VAS score, and knee ROM (
P
<
0.05
). And higher postoperative OST and tPINP levels while lower β-CTX were determined in the observation group (
P
<
0.05
). Conclusions. PRP+TKA can validly improve the levels of bone metabolism markers in patients with TA of the knee and promote their knee functional recovery, with favorable safety.