Background: Treatment of patients with knee osteoarthritis and proximal tibial fracture is a challenging problem. Optimal management of these patients is still controversial. This study aims to evaluate the radiological and functional results treated by one-stage long stem tibial TKA for elderly patients with proximal tibial fractures and knee osteoarthritis. Patients & Methods: Nineteen patients presented with proximal tibial stress fracture associated with rheumatoid arthritis and degenerative knee osteoarthritis with varus deformity were operatively treated with TKA with long tibial stem from the period of June 2016 to June 2018. There were 12 females and seven male patients all were above 55.8 years old (52-68 years). The diagnosis of stress fractures was confirmed using radiographic images. A standing antero-posterior X-ray obtained for all patients preoperatively and postoperatively. Union of the fracture was evaluated using anteroposterior (AP) and lateral leg x-rays. Results: The mean follow-up period was 14.2 months range, (6–24 months). The mean knee score and function score in Knee Society scoring (KSS) were 91.52 (SD: 4.45) and 72.03 (SD: 26.68) respectively. Based on function score, 10 knees (52.6%) had score of 80 to 100 (excellent result), 4 knees (21%) 60 to 80 (good results), 3 knees (15.78%) 40 to 60 (fair results) and 2 knees (10.52%) below 40 (poor results). The average preoperative and postoperative knee range of motion was 88.82°± 20.30° (60-130) and 105.25°±15.20° (90-125), respectively and improved postoperatively. The mean Preoperative femorotibial angle was 19.5o range (15.8-25.5o) varus and 3.2° varus postoperative. All the fractures were united at five to six months follow-up. One patient with delayed union. Conclusion: Single-stage total knee arthroplasty (TKA) with long tibial stem addresses both the problems by replacing arthritic knee surfaces, restoring limb alignment, and bypassing the fracture site which aids in union and helps faster recovery in elderly patients.