Introduction: Patellar fractures constitute about 1% of all skeletal injuries and disproportionately affect elderly women because of osteoporosis and low-energy falls. Displaced transverse fractures disrupt the knee extensor mechanism and, if unaddressed, predispose to non-union and permanent disability. In many low- and middle-income settings, initial referral to traditional bone-setters remains common and frequently delays definitive care. Case presentation: A 66-year-old woman presented one month after a simple fall with a displaced transverse fracture of the left patella and Kellgren–Lawrence grade II osteoarthritis of the same knee. Prior care was limited to traditional bone-setting without improvement. On admission, she had a palpable patellar gap and an inability to actively extend the knee. Radiographs confirmed displacement of 10 mm. Single-stage open reduction and internal fixation with a modified tension band wire construct reinforced by circumferential cerclage was performed. Active-assisted flexion began on postoperative day 14; by four weeks, she had 30° of pain-free flexion, full active extension, and primary wound healing, and was discharged for structured outpatient physiotherapy. Conclusion: A combined tension band wire plus circumferential cerclage construct provided reliable fixation and an encouraging early functional result despite a one-month delay and prior bone-setter manipulation. Prompt referral and structured rehabilitation remain pivotal for minimising non-union, hardware failure, and long-term disability in geriatric patellar fractures.