Trauma-related postoperative redisplacement after tension-band fixation for patellar fracture in Parkinson's disease: a case report and focused literature review.

RATIONALE: Patellar fractures in patients with Parkinson's disease (PD) are rarely reported, and evidence regarding optimal fixation and postoperative management remains limited. In this population, recurrent falls, abnormal muscle tone, and impaired bone quality may increase the risk of treatment failure. PATIENT CONCERNS: A 78-year-old man with long-standing PD presented with a patellar fracture after a low-energy fall and subsequently developed trauma-related postoperative redisplacement after a recurrent fall following primary tension-band fixation. DIAGNOSES: The patient was diagnosed with a displaced left patellar fracture (AO/OTA 34-C3) complicated by secondary traumatic redisplacement after a postoperative fall. INTERVENTIONS: The patient initially underwent tension-band fixation using two patellar pins, supplemented by suture-based soft-tissue reinforcement. After postoperative traumatic redisplacement, revision surgery with augmented fixation and additional suture-based soft-tissue reinforcement was performed. OUTCOMES: Radiographic follow-up demonstrated partial fracture union with residual nonunion and fragment avulsion. After revision surgery, knee range of motion (ROM) was 0°-20° at postoperative days 1-3, and at 1 month the visual analogue scale pain score was 1, with Lysholm and Bostman scores of 22 and 5, respectively. At 9 months, ROM was 0° to 30°, with full extension to 0°. Although CT showed partial union with residual nonunion and fragment avulsion, the patient was able to ambulate independently with a slow gait and perform daily activities. No Lysholm, Bostman, or Knee Society Score was obtained at the final follow-up. LESSONS: This case suggests that patellar fracture fixation in patients with PD may be particularly challenging. Recurrent falls and other PD-related factors may contribute to postoperative redisplacement and construct compromise. This case also highlights the need to consider careful surgical planning, appropriate postoperative protection, fall-risk mitigation, and bone health evaluation in similar high-risk patients.